intel turbo bosst tech

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Intel Turbo Boost Technology

Department of ECE, MBCCET, Peermade Page 1

INTRODUCTION

INTEL TURBO BOOST TECHNOLOGY is the fascinating technology which

automatically provides performance on demand. Intel Turbo Boost Technology is one of

the many exciting features that Intel has built into latest-generation Intel

microarchitechture codename Nehalem processor cores to run faster than the base

operating frequency if it's operating below power, current, and temperature specification

limits. Intel Turbo Boost technology, as the name suggests, helps boost the performance

of your computer's multi-core processor. The program, in its most simple terms, operates

by increasing the speed of each core on a system's chipset, drawing power away from

parts of the CPU not currently being used while providing that extra power to the chip's

active processors.

Basically, if the current application workload isn't keeping all four cores fully busy

and pushing right up against the chip's TDP (Thermal Design Power) limit, Turbo Boost

can increase the clock speed of each core individually to get more performance out of the

chip.

It's easy to see how this works when just one or two cores are being actively used;

whatever power the other two or three cores would have consumed can be redirected over

to the active cores, allowing them to run at higher speeds. Basically, if the current

application workload isn't keeping all four cores fully busy and pushing right up against

the chip's TDP (Thermal Design Power) limit, Turbo Boost can increase the clock speed

of each core individually to get more performance out of the chip.

It's easy to see how this works when just one or two cores are being actively used;

whatever power the other two or three cores would have consumed can be redirected over

to the active cores, allowing them to run at higher speeds.


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The quad-core mode of Turbo Boost is a little more subtle; it works when the four cores

aren't running a worst-case workload--for example, integer-heavy processing, since it's

generally floating-point calculations that consume the most power--so they aren't

bumping into the TDP limit. Turbo Boost can increase the frequency of all four cores

until they're running as fast as they can for the current workload.


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MICROPROCESSOR

The microprocessor is one of the important components of a digital computer. It acts as

the brain of the computer system. Before going to the detailed description of the

microprocessor, let us see what a digital computer is. A digital computer makes

processing of numbers.

Computers are the most powerful tool man has ever created. A digital computer is a

programmable machine. Its main components are: cpu, memory, input device and output

device. The schematic diagram of a digital computer is shown below:

Schematic diagram of a digital computer

The CPU executes the instructions. The input device is used to feed programs and

data to the computer. The memory is a storage device. It stores programs, data and result.

The output device displays or prints the data or results according to the instruction given

to the computer. The central processing unit built into a single IC is called

microprocessor. A digital computer in which only one microprocessor has been built to

MEMORY

CPU

OUTPUT DEVICEINPUT DEVICE


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act as the CPU is called the microcomputer. A desktop computer and portable computers

like laptop, notebook, palmtop, etc. contain one microprocessor to act as the CPU and

hence they come under the category of microcomputer.

MULTICORE PROCESSOR

In computing, a processor is the unit that reads and executes program instructions, which

are fixed-length (typically 32 or 64 bit) or variable-length chunks of data. The data in the

instruction tells the processor what to do. The instructions are very basic things like

reading data from memory or sending data to the user display, but they are processed so

rapidly that we experience the results as the smooth operation of a program.

Processors were originally developed with only one core. The core is the part of the

processor that actually performs the reading and executing of the instruction. Single-core

processors can only process one instruction at a time. (To improve efficiency, processors

commonly utilize pipelines internally, which allow several instructions to be processed

together, however they are still consumed into the pipeline one at a time.)

A multi-core processor is a processing system composed of two or more

independent cores. One can describe it as an integrated circuit to which two or more

individual processors (called cores in this sense) have been attached.[1] Manufacturers

typically integrate the cores onto a single integrated circuit die (known as a chip

multiprocessor or CMP), or onto multiple dies in a single chip package. A many-

core processor is one in which the number of cores is large enough that traditional multi-

processor techniques are no longer efficient this threshold is somewhere in the range

of several tens of cores and probably requires a network on chip.

A dual-coreprocessor contains two cores, a quad-core processor contains four cores,

and a hex-core processor contains six cores. A multi-core processor

implements multiprocessing in a single physical package. Designers may couple cores in

a multi-core device together tightly or loosely. For example, cores may or may not

share caches, and they may implement message passing or shared memory inter-core

communication methods. Common network topologies to interconnect cores include bus,


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ring, 2-dimensional mesh, and crossbar. Homogeneous multi-core systems include only

identical cores, unlike heterogeneous multi-core systems. Just as with single-processor

systems, cores in multi-core systems may implement architectures

like superscalar, VLIW, vector processing, SIMD, or multithreading.

Multi-core processors are widely used across many application domains including

general-purpose, embedded, network, digital signal processing (DSP), and graphics.

The amount of performance gained by the use of a multi-core processor depends very

much on the software algorithms and implementation. In particular, the possible gains are

limited by the fraction of the software that can be parallelized to run on multiple cores

simultaneously; this effect is described by Amdahl's law. In the best case, so-

called embarrassingly parallel problems may realize speedup factors near the number of

cores, or beyond even that if the problem is split up enough to fit within each processor's

or core's cache(s) due to the fact that the much slower main memory system is avoided.

Many typical applications, however, do not realize such large speedup factors. The

parallelization of software is a significant on-going topic of research.

Advantages

The proximity of multiple CPU cores on the same die allows the cache

coherency circuitry to operate at a much higher clock-rate than is possible if the signals

have to travel off-chip. Combining equivalent CPUs on a single die significantly

improves the performance ofcache snoop (alternative: Bus snooping) operations. Put

simply, this means that signals between different CPUs travel shorter distances, and

therefore those signals degrade less. These higher-quality signals allow more data to be

sent in a given time period, since individual signals can be shorter and do not need to be

repeated as often.

The largest boost in performance will likely be noticed in improved response-time while

running CPU-intensive processes, like antivirus scans, ripping/burning media (requiring

file conversion), or searching for folders. For example, if the automatic virus-scan runs

while a movie is being watched, the application running the movie is far less likely to be


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starved of processor power, as the antivirus program will be assigned to a different

processor core than the one running the movie playback.

Assuming that the die can fit into the package, physically, the multi-core CPU designs

require much less printed circuit board (PCB)space than do multi-chip SMP designs.

Also, a dual-core processor uses slightly less power than two coupled single-core

processors, principally because of the decreased power required to drive signals external

to the chip. Furthermore, the cores share some circuitry, like the L2 cache and the

interface to the front side bus (FSB). In terms of competing technologies for the available

silicon die area, multi-core design can make use of proven CPU core library designs and

produce a product with lower risk of design error than devising a new wider core-design.

Also, adding more cache suffers from diminishing returns.

Disadvantages

Maximizing the utilization of the computing resources provided by multi-core processors

requires adjustments both to the operating system (OS) support and to existing

application software. Also, the ability of multi-core processors to increase application

performance depends on the use of multiple threads within applications. The situation is

improving: for example the Valve Corporation's Source engine offers multi-core support,

and Crytekhas developed similar technologies forCryEngine , which powers their

game, Crysis. Emergent Game TechnologiesGamebryo engine includes their Floodgate

technology which simplifies multicore development across game platforms. In

addition, Apple Inc.'s latest OS, Snow Leopard has a built-in multi-core facility

called Grand Central Dispatch for Intel CPUs.

Integration of a multi-core chip drives chip production yields down and they are more

difficult to manage thermally than lower-density single-chip designs. Intel has partially

countered this first problem by creating its quad-core designs by combining two dual-

cores on a single die with a unified cache, hence any two working dual-core dies can be

used, as opposed to producing four cores on a single die and requiring all four to work to


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produce a quad-core. From an architectural point of view, ultimately, single CPU designs

may make better use of the silicon surface area than multiprocessing cores, so a

development commitment to this architecture may carry the risk of obsolescence. Finally,

raw processing power is not the only constraint on system performance. Two processing

cores sharing the same system bus and memory bandwidth limits the real-world

performance advantage. If a single core is close to being memory-bandwidth limited,

going to dual-core might only give 30% to 70% improvement. If memory bandwidth is

not a problem, a 90% improvement can be expected. It would be possible for an

application that used two CPUs to end up running faster on one dual-core if

communication between the CPUs was the limiting factor, which would count as more

than 100% improvement.

Diagram of a generic dual-core processor, with CPU-local level 1 caches, and a shared,

on-die level 2 cache is shown above.


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OVERLOCKING OF MICROPROCESSORS

Simply put, overclocking refers to running a system component at higher clock speeds

than are specified by the manufacturer. At first blush, the possibility of overclocking

seems counter-intuitiveif a given chip were capable of running at higher speeds;

wouldn't the manufacturer sell it as a higher speed grade and reap additional revenue?

The answer is a simple one, but it depends on a basic understanding of how chips are

fabricated and sorted.

Chip fabrication produces large wafers containing hundreds if not thousands of individual

chips. These wafers are sliced to separate individual dies, which are then tested to

determine which of the manufacturers offered speed grades they can reach. Some chips

are capable of higher speeds than others, and they're sorted accordingly. This process is

referred to as binning.

There's considerably less demand for faster chips than for slower ones, though. The Core

2 Extreme QX9650 may be the fastest CPU Intel can produce, but with street prices

hovering around $1200, it costs quite a bit more than most folks are willing to spend on a

CPU. The Core 2 Quad Q6600, which sells for less than $300, is in much higher demand

because it fits within the budget of a greater number of consumers. And demand for low-

end chips is even greater still.

Chipmakers often find themselves in a position where the vast majority of the chips they

produce are capable of running at higher clock speeds, since all chips of a particular

vintage are produced in the same basic way. So chipmakers end up designating faster

chips as lower speed grades in order to satisfy market demand. This practice is of

particular interest to overclockers because it results in inexpensive chips with "free"

overclocking headroom that's easy to exploit. That's the magic of binning: it's often quite


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generous. A great many of the CPUs sold these days, especially the low-end and mid-

range models come with some built-in headroom.

Overclocking can do much more than exploit a chip's inherent headroom, though. It's also

possible to push chips far beyond speeds offered by even the most expensive retail

products. Such overclocking endeavors usually require more extreme measures, such as

extravagant cooling solutions, so they're a little beyond the scope of what most folks will

want to tackle.

The most important ingredient in any overclocking endeavor is a good chip. If you're

looking to exploit the "free" overclocking headroom made possible by binning, you're

best off looking at lower speed grades. If you're after the maximum overclock, you'll

probably want to pick the number of cores and the amount of cache that you want, and

then select the lowest speed grade available with those characteristics. If you have a

choice between chips with different front-side bus speeds, it's probably best to pick the

chip with the lower default bus speed. A slower front-side bus can make life easier for the

motherboard, and you may even be able to overclock the processor without pushing the

board beyond its specifications.

Overclocking forums are also rife with discussions of specific CPU stepping and batch

numbers that have higher success rates than others. If you're willing to do a little

researchand if you can coax retailers into giving you more detailed information on

chips they have in stockyou can increase your chances of success. Gathering stepping

and batch information is particularly useful if you intend to push clock speeds well

beyond any binning freebies.

Success is never guaranteed with overclocking. Your mileage will a most certainly vary,

and you might even end up with a complete dud incapable of running more than a few

MHz faster than its stock speed.


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Just because we're focused on processor overclocking doesn't mean that other system

components aren't important. A system's motherboard, cooling system, power supply, and

even memory can affect the success of an overclocking attempt. These don't necessarily

need to be expensive high-end partsthat would defeat much of the value proposition

behind overclockingbut you'll be better off with quality components from reputable

manufacturers. On the motherboard front, you want to ensure that the BIOS has ample

overclocking options, including the ability to manipulate bus speeds and system voltages.

The more control we have over system variables, the more freedom we'll have to tweak

settings carefully in pursuit of higher clock speeds. Motherboard cooling becomes more

important when you turn up clock speeds, as well. You don't need a mess of heat pipes

snaking every which way on the board, but try to stay away from boards with tiny chipset

coolers that don't offer much surface area to dissipate heat. Depending on how far you

intend to push clock speeds, you may also want to consider beefing up your system's

CPU cooling. Overclocked chips tend to run hotter than those at stock speeds,

particularly when you start increasing the CPU voltage, and you don't want a stock cooler

holding your system back. Aftermarket coolers designed for overclocking feature

significantly more surface area than the stock coolers AMD and Intel bundle with their

processors. Aftermarket coolers also tend to have much larger fans to generate more

airflow, often while making less noise. Decent coolers can be had for as little as $30, so

they won't put a big dent in your budget.

We always recommend that users spend a little extra to get a quality power supply for

their systems, and this goes double if you want to overclock. Our concern here isn't

getting gobs of extra wattage, but ensuring that the PSU delivers clean power to the

system.

Fancy memory isn't always necessary if you're looking to overclock a processor, but

DIMMs rated for operation at higher frequencies can give you a little more freedom when

playing with clock speeds. Memory module manufacturers often guarantee their products

to run at higher clock frequencies, even if those speeds aren't officially endorsed by the

JEDEC standards body that governs system memory.


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Even more important than individual component choices is having a completely stable

system before you dive into overclocking. If you're building a new system from scratch,

stress test it at stock speeds to ensure that everything is working properly. The last thing

you want is to burn an afternoon trying in vain to overclock a system hampered by a

faulty component that isn't even stable at stock speeds.

Theobligatory warning

Overclocking will probably void your warranty, and it has the potential to damage not

only the hardware being overclocked, but other system components, as well. This is

where The Tech Report absolves itself of any responsibility for damaged hardware,

voided warranties, puffs of magic smoke, core meltdowns, and bruised egos that may

result from unsuccessful overclocking attempts. Or, heck, even successful ones. We

should also warn you that this guide covers overclocking through the motherboard BIOS.

If you're not comfortable poking around in the BIOS, you probably shouldn't be

overclocking in the first place. Before you begin overclocking your CPU, you shouldstart by making a backup of any important data on your system. You may even want to

consider using a disk imaging program like Symantec Ghost to make a complete image of

your boot partition. We've seen more than one OS installation rendered unbootable by

file corruption caused by an unstable processor in the midst of an overclocking attempt.

The trial-and-error process of seeking a stable overclocked configuration necessarily

involves some risk on this front, so make provisions ahead of time.


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OVERVIEW OF INTEL TURBO BOOST TECHNOLOGY

Intel Core Microarchitechture (Nehalem) based processors incorporate a new feature:

Intel Turbo Boost technology. Under some configurations and workloads, Intel Turbo

Boost technology enables higher performance through the availability of increased core

frequency. Intel Turbo Boost technology automatically allows processor cores to run

faster than the base operating frequency if the processor is operating below rated power,

temperature, and current specification limits. Intel Turbo Boost technology can be

engaged with any number of cores or logical processors enabled and active. This results

in increased performance of both multi-threaded and single-threaded workloads. It is

possible for BIOS to contain a set-up option to enable or disable Intel Turbo Boost

technology and it operates under operating system (OS) control by engaging when the OS

requests the highest performance state (P0). For ACPI aware operating systems, no

changes are required to support Intel Turbo Boost technology.


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The maximum frequency is dependent on the number of active cores and varies based on

the specific configuration on a per processor number basis. The amount of time the

processor spends in the Intel Turbo Boost technology state will depend on workload and

operating environment.

Intel Turbo Boost technology is available only on supported processor versions. With

Intel Turbo Boost technology, the processor is capable of maximizing core frequency

while ensuring that it does not exceed its electrical and thermal specifications. This

means workloads that are naturally lower in power or lightly threaded may take

advantage of headroom in the form of increased core frequency. Continual measurements

of temperature, current draw, and power consumption are used to dynamically assess

headroom.

DEPENDENCIES OF THE TECHNOLOGY

Intel Turbo Boost technology core frequency upside availability is ultimately constrained

by power delivery limits, but within those constraints, it is limited by the following

factors:

The estimated current consumption of the processor

The estimated power consumption of the processor

The temperature of the processor

The number of active cores at any given instant dictates the upper limit of Intel Turbo

Boost technology. For this discussion, a core is considered active if it is in the C0 or

C1 state; cores in the C3 or C6 state are considered inactive. The upper limits

will vary on a per processor number basis. For example, one particular processor may

allow up to two frequency steps (266.66 MHz) when just one core is active and one

frequency step (133.33 MHz) when two or more cores are active. Therefore, higher deep


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C-state residency (C3 or C6) on some cores will generally result in increased core

frequency on the active cores. The upper limits are further constrained by temperature,

power, and current. These constraints are managed as a simple closed-loop control

system. If measured temperature, power and current are all below factory-configured

limits and the OS is requesting P0, the processor automatically steps up core frequency

(+133.33MHz) until it reaches the upper limit dictated by the number of active cores.

When temperature, power or current exceed factory configured limits and you are above

the base operating frequency, the processor automatically steps down core frequency (-

133.33 MHz) in order to reduce temperature, power and current. The processor then

monitors temperature, power, and current and continuously re-evaluates.

Note: When Intel Turbo Boost technology is requested by the OS, the processor will

commonly operate between the max Intel Turbo Boost technology frequency and the base

operating frequency.

All active cores in the processor will operate at the same frequency. Even at frequencies

above the base operating frequency, all active cores wil run at the same frequency and

voltage. Due to the way the BIOS and OS communicate Intel Turbo Boost technology,

software may never detect core clock frequencies above the base operating frequency.

This is not reflective of actual core frequency.

OPERATING FREQUENCY

Due to the methods used by BIOS to transparently expose Intel Turbo Boost technology

functions to the operating system, software that wishes to calculate (and/or display) the

current operating core frequency may need to be updated.

Most currently available software that calculates frequency relies on the ACPI P-state

structures that are provided by the BIOS or calls an application programming interface

(API) that relies on these structures. The frequency field in the P0 ACPI _PSS object

does not reflect actual Intel Turbo Boost technology frequencies. Instead, it always shows

the P0 frequency as P1 frequency plus 1MHz. Due to this, software that uses the P state

structures, directly or indirectly, will not properly display Intel Turbo Boost technology

frequencies.


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NOTE: Operating Systems may also be impacted and may not report accurate frequency.

The algorithm below can be used to estimate the current operating frequency of a

processor. The algorithm will calculate the average frequency of the active cores over a

1-second window. The time window can be adjusted if increased monitoring is desired.

DYNAMICALLY INCREASING PERFORMANCE

Intel Turbo Boost Technology is activated when the Operating System (OS) requests the

highest processor performance state (P0).

The maximum frequency of Intel Turbo Boost Technology is dependent on the number of

active cores. The amount of time the processor spends in the Intel Turbo Boost

Technology state depends on the workload and operating environment.

Any of the following can set the upper limit of Intel Turbo Boost Technology on a given

workload:


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Number of active cores Estimated current consumption Estimated power consumption Processor temperature

When the processor is operating below these limits and the user's workload demands

additional performance, the processor frequency will dynamically increase by 133 MHz

on short and regular intervals until the upper limit is met or the maximum possible upside

for the number of active cores is reached.

As an independent and complementary feature, Intel Hyper-Threading Technology

(Intel HT Technology) increases performance of both multi-threaded and single

threaded workloads.


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FREQUENCYALGORITHM

The following are the general steps to implement the frequency-monitoring algorithm.

1. Compute and save the reference frequency. Bits 15:8 of the PLATFORM_INFOMSR (0CEH) are the Base Operating Ratio. Multiply by the bus clock

frequency (BCLK) to get the base operating frequency. The standard bus clock

frequency is 133.33 MHz

2. Enable fixed Architectural Performance Monitor counters 1 and 2 in the Global

Performance Counter Control IA32_PERF_GLOBAL_CTRL (38FH) and the

Fixed-Function Performance Counter Control IA32_FIXED_CTR_CTL (38DH). Repeat

this step for each logical processor in the system. Fixed Counter 1

(CPU_CLK_UNHALTED.CORE) Counts the number of core cycles while the

Core is not in a halted state. Fixed Counter 2 (CPU_CLK_UNHALTED.REF) counts the

number of reference (base operating frequency) cycles while the core is not in a halted

state.

3.Configure an auto-rearming timer with 1- Second duration using an OS API.

4.Repeat steps 5 through 10 until the Application exits.

5. Wait for the 1-second timer to expire.


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6. Read the Fixed-Function Performance Counter 1 IA32_FIXED_CTR1 (30AH)and the Fixed- Function Performance Counter 2 IA32_FIXED_CTR2 (30BH).

Repeat this step.For each logical processor in the system.

7. Compute the number of unhalted core cycles and unhalted reference cycles thathave expired since the last iteration by subtracting The previously sampled values

from the currently sampled values.

8. Compute the actual frequency value for each Logical processor as follows: Fcurrent =

Base Operating Frequency * (Unhalted Core Cycles /Unhalted Ref Cycles)

9. Update with GUI to display the newly Computed values (for accurate display, choose

the maximum frequency of all logical Processors).

10. Save Unhalted Core Cycles and Unhalted RefCycles for use in the next iteration.

NOTE: Step 9 is required due to the fact that idle Cores will be woken up to read their

frequency and that will change the results of those idle Cores. For displaying the

frequency of the active Cores, ignore these lower results.

What is Intel Turbo Boost Technology and how does it work?


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Intel Turbo Boost Technology is a way to automatically run the processor core faster than

the marked frequency if the part is operating under power, temperature, and current

specification limits of the Thermal Design Power (TDP). This results in increased

performance of both single and multi-threaded applications.

Whichprocessor familiessupport Intel Turbo Boost Technology?

y Intel Core i7 mobile and desktop processorsy Intel Core i7 processor extreme editiony Intel Core i7 mobile processor extreme editiony Intel Core i5 mobile and desktop processors

What factors influence Intel Turbo Boost Technology operation?

While Intel Turbo Boost Technology availability is independent of the number of active


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cores, the operation is dependent on having headroom (cores operating under TDP)

available in one or more cores. The amount of time the system spends in turbo boost will

ultimately depend on workload, operating environment, and platform design.

How is Intel Turbo Boost Technology enabled or disabled?

Intel Turbo Boost Technology is usually enabled by default by a switch in the bios where

you can either enable or disable operation. Other than this, there are no user controllable

settings to change Intel Turbo Boost Technology operation either in the hardware settings

or operating system. Once enabled, Intel Turbo Boost Technology works automatically

under operating system control.

Isturbo frequencythesame forallactivecoresintheprocessor?

Yes.

Can Intel Turbo Boost Technologybeenabledordisabledbycore?

No. You can sometimes disable cores in the bios but this is not recommended unless

there is a specific reason you need to do this.

Istherea waytospecifythemaximum Intel Turbo Boost Technology

frequency?

There is no way to specify the maximum frequency. Once the system is in turbo boost,

the processor automatically determines the maximum frequency it can operate at based

on operating conditions.


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Whatmodesofoperationareavailable with Intel Turbo Boost

Technology forthe Intel Corei7-900processorseriesandthe Intel Core

i5-600processorseries?

y 1 bin (+133 MHz) across one active corey 2 bins (+266 MHz) across one active corey 1 bin (+133 MHz) across two active coresy 1 bin (+133 MHz) across three active cores

How can I tellif Intel Turbo Boost Technologyis working?

The Intel Turbo Boost Technology Monitor is a tool that will show you Intel Turbo Boost

Technology in action.

Intel Processor Identification Utility will be able to show you that it is working at the

highest Turbo Boost frequency if you disable the other cores in the bios. If you set theamount of cores to one in the bios and run the Intel Processor Identification Utility, it will

show the highest Turbo Boost frequency. Make sure that you reset the switch in the bios

to reactivate all cores in the bios if you made that change.

How importantissystemintegrationandsystemdesigninregardto

Intel Turbo Boost Technology?

Since Intel Turbo Boost Technology runs when the processor is operating under the

power, temperature, and current specification limits of Thermal Design Power (TDP),

good system integration and thermal design becomes more important than ever to extract

the benefits of Intel Turbo Boost Technology.


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INTEL TURBO BOOST TECHNOLOGY MONITOR

Intel turbo boost technology monitor is a simple sidebar gadget for Windows Vista and

Windows 7. It lets developers and users check the microprocessor's application of Turbo

Boost. It is a simple gadget that lets you answer the question: What is Intel Turbo Boost

Doing?

The idea of overclocking a microprocessor to higher frequencies when it is under a heavy

workload isnt a new one. There is a whole industry providing sophisticated hardware

capable of pushing each new microprocessor model to its overclocking limits. However,

there is a great difference between dynamic overclocking at a microprocessor level and

Intel Turbo Boost Technology. The latter works at a physical core level, by overclocking

one or more physical cores, specifically the active cores.

If you want to check the status of Turbo Boost in real-time in Windows, you can install

the Intel Turbo Boost Technology Monitor and add the gadget to your desktop. Its

installation is very easy; you just have to download TurboBoostSetup.exe, run the

installer and add the gadget to your desktop.

When one of the active cores runs faster, taking advantage of the Turbo mode, a blue bar

appears in the gadget and displays the current frequency for the active core(s). If the blue

bar doesnt appear, it means that the Turbo mode isnt working, as in Figure 1. However,

the frequency for some of the cores could be less than the nominal frequency shown in

the gadget.


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Figure 1: Intel Turbo Boost Technology Monitor withoutthebluebar. The Turbo

modeisnt working.

When the Turbo mode is activated and one or more cores increase their frequency, the

blue bar will appear in the gadget and it will display the new frequency, as in Figure 2.

Figure 2: Intel Turbo Boost Technology Monitordisplayingthebluebarandthe

new frequency fortheactivecores, 2.13 GHz insteadofthebase frequency, 1.73

GHz.


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Watching the gadget you will understand the way the Turbo mode increases and

decreases the frequency as more cores get active or the conditions change. By default, the

gadget animates the blue bar and will display the new frequencies.

The gadget is really helpful to understand the behavior of this dynamic overclocking

feature. The frequency displayed corresponds to the more active cores. Nonetheless, as

more cores require processing power, the effect of the Turbo mode could be dissipated.

Figure 4 displays the results of running an application that uses the processing power

available in all the cores, monitored using All CPU Meter. As you can see, the Turbo

mode disappears because all the cores are under heavy load at the same time.


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NEHALEM MICROARCHITECTURE

Since the introduction of Intel Core microarchitecture in 2006 and its 2007 45nm

enhancementsthe Intel Core microarchitecture (Penryn) family of processorsthe


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blistering performance and energy efficiency of Intel microprocessors have delivered

unprecedented capabilities to computer users. Now a new microarchitecture named

Nehalem (the foundation of the Intel Xeon processor 3500 and 5500 series) builds on

these earlier microarchitectural marvels, rewriting the book on processor scalability,

performance, and energy efficiency.Intel microarchitecture (Nehalem) is a dynamically

scalable and design-scalable microarchitechture. At runtime, it dynamically manages

cores, threads, cache, interfaces,and power to deliver outstanding energy efficiency and

performance on demand.At design time, it scales easily, enabling Intel to provide

versions optimized for each server, desktop, and notebook market.Intel will deliver

versions differing in the number of cores, caches, interconnect capability, and memory

controller capability,as well as in the inclusion of an integrated graphics controller. This

allows Intel to deliver a wide range of price, performance, and energy efficiency targets

for servers,workstations, desktops, and laptops.Intel microarchitectures (Nehalems)

energy efficiency and performance comes at a critical crossroads in computing. In the

past, when a computers energy efficiency wasnt a concern, nearly every architecture

feature that could improve processor performance would be included without

worrying about the power cost. But in an age of increasing concern for limited

resources and increased energy costs,every segment (server, workstation,desktop, and

mobile) is power-constrained and designing a microarchitecture requires a different

approach. Processor manufacturers must consider the power cost for whether the

processor is intended for the home, data center, or ultra-light laptop. Intel weighed every

architectural feature added to Intel microarchitecture (Nehalem) against a strict

power/performance efficiency threshold. If the feature couldnt add more than a one

percent performance gain for a less than three percent power cost, Intel wouldnt add it.

By measuring the benefit of the performance gain against the power cost, Intelwas able to design Intel microarchitecture (Nehalem) to deliver greater power

efficiency at any power envelope.


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A good example of how Intel microarchitecture(Nehalem) enables the scaling of energy

efficiency and performance can be seen in the Intel Xeon processor 3500 and 5500 series.

These two server/workstation processor series incorporate a number of Intels innovative

technologies to deliver intelligent performance.

Intel Turbo Boost Technology.

This technology delivers performance on demand, allowing processors to operate above

the rated frequency to speed specific workloads and drop back down to reduce power

consumption during low utilization periods.

Intel Hyper-Threading Technology

This well-known Intel innovation provides more performance for applications designed

for parallel, multi-threaded execution by reducing computational latency and making

optimal use of every cycle. Intel Hyper-Threading Technology benefits from this latest

Intel microarchitectures larger caches and massive memory bandwidth, delivering

greater throughput and responsiveness for multi-threaded applications.

Intel QuickPath Technology.

This new, scalable, shared memory architecture integrates a memory controller into each

microprocessor and connects processors and other components with a new highspeed

interconnect. It speeds traffic between processors and I/O controllers for bandwidth-

intensive applications, delivering up to 3.5 times the bandwidth for technical computing.

Intel Intelligent Power Technology.

This feature enables policy-based control that allows processors to operate at optimal

frequency and power. Operating systems can make this determination automatically, or

administrators can designate which applications require high-frequency processing and

which should be executed at lower frequencies to conserve power.

Intel Virtualization Technology.This latest generation version of Intel Virtualization Technology enhances virtualization

performance by up to 2.1 times 5 with new hardware assist capabilities across server and

workstation element.


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TERMS TO BE EXPLAINED

1.BIOS

In IBM PC Compatible computers, the basic input/outputsystem (BIOS) , also known

as the System BIOS, is a de facto standard defining a firmware interface.

The BIOS of a PC software is built into the PC, and is the first code run by a PC when

powered on ('boot firmware'). The primary function of the BIOS is to load and startanoperating system. When the PC starts up, the first job for the BIOS is to initialize and

identify system devices such as the video display card, keyboard and mouse, hard disk,

CD/DVD drive and other hardware. The BIOS then locates software held on a peripheral

device (designated as a 'boot device'), such as a hard disk or a CD, and loads and executes

that software, giving it control of the PC. This process is known as booting, or booting

up, which is short for bootstrapping.

BIOS software is stored on a non-volatile ROM chip built into the system on the mother

board. The BIOS software is specifically designed to work with the particular type of

system in question, including having a knowledge of the workings of various devices that

make up the complementary chipset of the system. In modern computer systems,

theBIOS chip's contents can be rewritten allowing BIOS software to be upgraded.

A BIOS will also have a user interface (or UI for short). Typically this is a menu system

accessed by pressing a certain key on the keyboard when the PC starts. In the BIOS UI, a

user can:

configure hardware set the system clock enable or disable system components select which devices are eligible to be a potential boot device


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set various password prompts, such as a password for securing access to the BIOS UIfunctions itself and preventing malicious users from booting the system from

unauthorized peripheral devices.

The BIOS provides a small library of basic input/output functions used to operate and

control the peripherals such as the keyboard, text display functions and so forth, and these

software library functions are callable by external software. In the IBM PC and AT,

certain peripheral cards such as hard-drive controllers and video display adapters carried

their own BIOS extension ROM, which provided additional functionality. Operating

systems and executive software, designed to supersede this basic firmware functionality,

will provide replacement software interfaces to applications.

The role of the BIOS has changed over time; today BIOS is a legacy system, superseded

by the more complex Extensible Firmware Interface (EFI), but BIOS remains in

widespread use, and EFI booting has only been supported in x86 Windows since 2008.

BIOS is primarily associated with the 16-bit and 32-bit architecture eras (x86-32), while

EFI is used for some 32-bit and most 64-bit architectures. Today BIOS is primarily used

for booting a system, and for certain additional features such as power management

(ACPI) and video initialization (in X.org), but otherwise is not used during the ordinaryrunning of a system, while in early systems (particularly in the 16-bit era), BIOS was

used for hardware access operating systems (notably MS-DOS) would call the BIOS

rather than directly accessing the hardware. In the 32-bit era and later, operating systems

instead generally directly accessed the hardware using their owndevice drivers.

2.Advanced Configurationand Power Interface (ACPI)

In computing, the Advanced Configuration and Power Interface (ACPI) specification

provides an open standard for unified operating system-centric device configuration

and power management. ACPI, first released in December 1996, defines platform-

independent interfaces for hardware discovery, configuration, power management and

monitoring. The specification is central to Operating System-directed configuration and


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Power Management(OSPM); a term used to describe a system implementing ACPI,

which therefore removes device management responsibilities from legacy firmware

interfaces. The standard was originally developed by Intel, Microsoft, and Toshiba, and

last published as "Revision 4.0a", on April 5, 2010. As of 2010, developers of ACPI also

include HP and Phoenix

ACPI aims to consolidate and improve upon existing power and configuration standards

for hardware devices. It provides a transition from existing standards to entirely ACPI-

compliant hardware, with some ACPI operating systems already removing support for

legacy hardware. With the intention of replacing Advanced Power Management,

the Multiprocessors Specification and the Plug and Play BIOS Specification, the standard

brings power management into operating system control (OSPM), as opposed to the

previous BIOS central system, which relied on platform-specific firmware to determine

power management and configuration policy. The ACPI specification contains numerous

related components for hardware and software programming, as well as a unified

standard for device/power interaction and bus configuration. As a document that unifies

many previous standards it covers many areas, for system and device builders as well as

system programmers. Some software developers have trouble implementing ACPI andexpress concerns about the requirements that byte code from an external source must be

run by the system with full privileges. Linus Torvalds, creator of the Linux kernel, once

described it as "a complete design disaster in every way", in relation to his view that

"modern PCs are horrible".

Microsoft Windows 98 was the first operating system with full support for ACPI,

with Windows 2000, Windows XP, Windows Vista, Windows 7, Linux and PC versions

of SunOS all having at least some support for ACPI.

3. OSPM RESPONSIBILITIES

ACPI requires that once an OSPM-compatible operating system has activated ACPI on a

computer, it then takes over and has exclusive control of all aspects of power

management and device configuration. The OSPM implementation must expose an


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ACPI-compatible environment to device drivers, which exposes certain system, device

and processor states.

Power States

Global states

The ACPI specification defines the following seven states (so-called global states) for an

ACPI-compliant computer-system:

G0 (S0): Working G1, Sleepingsubdivides into the four states S1 through S4:

S1: All processor caches are flushed, and the CPU(s) stop executing instructions.Power to the CPU(s) and RAM is maintained; devices that do not indicate they

must remain on may be powered down.

S2: CPU powered off S3: Commonly referred to as Standby, Sleep, orSuspend to RAM. RAM remains

powered

S4: Hibernation orSuspend to Disk. All content of main memory is saved to non-volatile memory such as a hard drive, and is powered down.

G2 (S5), SoftOff: G2 is almost the same as G3MechanicalOff, but some componentsremain powered so the computer can "wake" from input from the keyboard,

clock, modem, LAN, or USB device.

G3,MechanicalOff: The computer's power consumption approaches close to zero, tothe point that the power cord can be removed and the system is safe for dis-assembly

(typically, only the real-time clock is running off its own small battery).

Furthermore, the specification defines aLegacy state: the state on an operating systemwhich does not support ACPI. In this state, the hardware and power are not managed via

ACPI, effectively disabling ACPI.

Device states

The device statesD0-D3 are device-dependent:


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D0 Fully-On is the operating state. D1 and D2 are intermediate power-states whose definition varies by device. D3 Offhas the device powered off and unresponsive to its bus.Processorstates

The CPU power states C0-C3 are defined as follows:

C0 is the operating state. C1 (often known as Halt) is a state where the processor is not executing instructions,

but can return to an executing state essentially instantaneously. All ACPI-conformant

processors must support this power state. Some processors, such as the Pentium 4,also support an Enhanced C1 state (C1E or Enhanced Halt State) for lower power

consumption.

C2 (often known as Stop-Clock) is a state where the processor maintains all software-visible state, but may take longer to wake up. This processor state is optional.

C3 (often known as Sleep) is a state where the processor does not need to keepits cache coherent, but maintains other state. Some processors have variations on the

C3 state (Deep Sleep, Deeper Sleep, etc.) that differ in how long it takes to wake the

processor. This processor state is optional.

Performancestates

While a device or processor operates (D0 and C0, respectively), it can be in one of

several power-performance states. These states are implementation-dependent, but P0 is

always the highest-performance state, with P1 to Pn being successively lower-

performance states, up to an implementation-specific limit ofn no greater than 16.

P1 less than P0, voltage/frequency scaled

Pn less than P(n-1), voltage/frequency scaled


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ADVA

NTA

GES

1. Intel Turbo Boost Technology is a way to automatically run the processor corefaster than the marked frequency if the part is operating under power,

temperature, and current specification limits of the Thermal Design Power (TDP).

2. This results in increased performance of both single and multi-threadedapplications..

3. Once the system is in turbo boost, the processor automatically determines themaximum frequency it can operate at based on operating conditions.


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CONCLUSION

Intel Turbo Boost Technology one of the latest technologies present in the Nehalem

microarchitecture based microprocessors. Nehalem microarchitecture incorporate several

other features such as Intel Hyper threading Technology, smart cache etc. Turbo Boost

technology is actually a secured way for overclocking. It increases the speed of the

Multicore processors if some predefined conditions are satisfied. While Intel Turbo Boost

Technology availability is independent of the number of active cores, the operation isdependent on having headroom (cores operating under TDP) available in one or more

cores. The amount of time the system spends in turbo boost will ultimately depend on

workload, operating environment, and platform design.


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REFERENCES

1. www.intel.com/technology/support

2. www.wikipedia.com

3. www.eHow.com

4. www.cnetnews.com

5. www.cpubenchmark.net

intel turbo bosst tech

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