how to replace the core i5 by a core i7 in a 27 imac

8/2/2019 How to Replace the Core i5 by a Core i7 in a 27 iMac

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How to replace the Core i5 by a Core i7 in a 27" iMac.

Despite the fact that the current model of 27" iMac running on Core i3, i5 or i7 appears - much like the previous 2009model - to leave little room for upgrade except for the few options available on the AppleStore (CPU, RAM, Hard Drive,

and now even SSD), this All in One computer can be upgraded with just a little bit of work, thanks to the new CoreiXX chips running inside, designed for desktop computers and not laptops.

Even though it doesn't appear to be "upgrade friendly", the 2009 27" Core i5 is the ideal investment. You can find it on

the Refurb for a good price and and outside also, if the warranty has expired, it makes it the perfect computer for this

kind of transformation.

The new Core iXX processors are mounted on a socket that has direct access to the memory thanks to an E/S

controller, which allowed Intel to eliminate several restrains such as the FSB (Front Side Bus) to use newer

technologies such as Hyper-Threading and TurboBoost. From there, to make a long story short, the Core iXX

processors don't have to use the mother board's clock multiplier any more in order to work. That way, if we replace

say, a Core i5 with a Core i7, the subject of this step by step, the processor will be running the machine and telling it

how to work and how to adapt.

In short, replacing a Core i3 or i5 by a Core i7 will not affect the rest of the computer since it follows the processor's

"directives". That way, when we replace the 2.66 GHz Core i5 by a 2.93 GHz i7 on the 27" iMac, the new CPU "tells" to

motherboard to tune in and to adapt, which it does without any hardware modification.

We invite you to discover how to do this easily by following this step by step article.

Each step is detailed in order to allow you to swipe processors without damaging the rest of your computer. You should

note however, that you can never be too careful. We advise you to read carefully all the details and to keep a digital

camera with you during the entire operation. This might be useful to make sure you didn't forget to screw some part

back or plug some cable back, and to find one screw still outside once the computer is back in one piece read

carefully, take you time and everything will be fine.

As a reminder, taking apart your computer can void the warranty if, while doing so, some pieces were falling or

breaking. Upgrading the RAM doesn't void the warranty.

If you go all the way and change the processor, the warranty will be automatically void. We advise you to do this

operation only on an iMac on which the warranty has expired, such as the 2009 models. Hardmac and Macbidouille

decline all responsibility in case of any damage caused to your computer if you decide to follow the process described

in this step by step.

Our choice.


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We decided to do the upgrade in order to gain significantly more performances. We therefore decided to replace the2.66 GHz Core i5 (precisely an i5-750) by a 2.93 GHz i7-870, holding 8 MB of L3 cache and having a TDP (ThermalDesign Power) of 95 Watts, close to the one of the Core i5.

Another advantage, we go from a 4 physical cores processor , which doesn't allow Hyper Threading to a 4 physicalcores processor that can simulate 4 other logical cores and which can reach, when "TurboBoosted" 3.6GHz, while thei5-750 can only reach 3.2 GHz. This should give it a lot more power and bring it to the level of the 2010 model atalmost no cost, while the option costs $200 on the AppleStore.

By taking advantage of the fact that both processors share the same socket, the Core i7 replaces the "old" i5 with o

problem. The design of the iMac - a great Apple achievement - helps a lot and the swipe takes less than 5 minutes

once you have laid down the mother board on the table, as you will see below.

The right tools.

As usual, it is very important that you use the right tools. Few of them are necessary, but some are very important

such as the ones you will use to remove the glass of the display. Don't worry if you don't have any specific tools for

removing glass, we have found a pretty funny alternative that you will see below.

You will need a couple of suction cups for the glass, Torx screwdrivers size 10 and 15 (having all sizes art close range

can be useful), a Phillips magnetized screwdriver size 00x40, a flat screwdriver, pliers (see picture) and optionally an

antistatic screwdriver, which is great to plug back little connectors.


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If you have a Swiss Army Knife, it should do the trick, but the Torx screwdrivers are essential. Also, you will need

some thermal compound, preferably some Arctic Silver.

CAUTION:

If you decide to open your iMac while it is still under warranty, we advise you to follow Apple's directions, meaning to

wear gloves and an antistatic bracelet. Unplug the iMac and wait fifteen minutes before touching the power supply

unit, after removing the LCD LED display, in order to avoid any electrostatic chock. We remind you once again that in

case of any broken part, the warranty will be irremediably void.

Taking apart the iMac

At first, taking apart a last generation iMac can seem somewhat tedious, even insuperable for most people, but it is

certainly not impossible. It does however require patience. Take time to follow each step, and bear in mind that

putting the computer back together will always be easier than taking it apart. Following this step by step doesn't

require any specific qualification, just some calmness and a little bit of perseverance. If you encounter difficulties

during one step of the process, getting angry would be useless, allow yourself a break, have a coffee or a hot


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chocolate, or go run an errand and come back when you have cleared your mind. Patience is still what matters most in

this process.

Step one: removing the glass.

It is one of the three most delicate steps of the process. Since the is kept in place by a set of magnets, the whole

extraction has to be done using the suction cups. To do so, you can choose (if you feel comfortable) to keep the iMac

up, but only if someone else is holding it. Put the cups in the middle at both ends of the glass about 5-6 inches from

the edge, remove the air and pull delicately but firmly towards you. The glass comes without too much effort. If you

are alone, it is better that you lay the iMac down, but don't forget to put a cot underneath the case in order to avoid

scratches. Once everything is set, proceed in the same manner. A good place to store the glass while you work on the

rest is the protection case that was on the iMac when you took it out of its box.

We couldn't hep but put a little bit of French humor in this step by step. If you don't have proper suction cups, as

surprising or ridiculous as it seems, a plunger will do the job


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Are we messing with you? Not at all. This tool, despite its normal primary use, works very well here. It even offers a

good grip and also allows to have a free hand to hold the case during the process.

CAUTION:

At first, taking apart a last generation iMac can seem somewhat tedious, even insuperable for most people, but it is

certainly not impossible. It does however require patience. Take time to follow each step, and bear in mind that

putting the computer back together will always be easier than taking it apart. Following this step by step doesn't

require any specific qualification, just some calmness and a little bit of perseverance. If you encounter difficulties

during one step of the process, getting angry would be useless, allow yourself a break, have a coffee or a hot

chocolate, or go run an errand and come back when you have cleared your mind. Patience is still what matters most in

this process.

Step two: removing the LCD display.

You've passed the first difficult step, this next one is also delicate, not complicated since the display is kept in place byonly 8 screws, but delicate because it is connected to the motherboard by 3 connectors, and two of them are pretty

fragile so be careful.


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Kept in place by only 8 screws, the display comes out quite easily. Beware of the magnets that seriously tend to attract

screws. It is not a problem when you open the iMac, but it can be more annoying when putting it back together.

Don't forget, there are 8 such screws to unscrew (see previous picture).


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No major difficulty to remove the display. The magnets can be a problem when putting the computer back together. As

you can see, some screws are located nearby.

The second difficult step, disconnecting the display from the motherboard. Start by pulling the top of the display a little

bit towards you 2 to 3" in order to disconnect the top connector, a flat one, about half an inch wide, which

"synchronizes" the backlight of the display.


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Next, the video connector - quite fragile - is located in the middle of the display. Pull the top of the display a little bit

more towards you (but too much!) and with your right hand, pull delicately the connector upward. The connector

comes out quite easily. You also have to remove the temperature sensor, a black and white wire located on the bottom

left of the video connector.

Finally, you have to pull a little bit more the top towards you to disconnect the power supply located on the left.


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This connector supplies the needed power of the backlit display. It comes out by pulling it downward. Once this is

done, you can pull the display out (do it carefully in case you have forgotten to disconnect a connector). We can now

go to the third step.

Step three: the motherboard

We arrive now to the core subject of this article. Several precautions have to be taken here. Be careful to identify each

screw you remove and most importantly, the connectors you disconnect. Don't worry, it is not complicated, you just

have to take your time. You are not in a rush. If you have decided to go all the way though this process, it means you

have both motivation and patience.

The first step here is to identify and remove the general power supply of the iMac. As we said earlier, it is very

important to unplug the iMac at least fifteen minutes before touching the power supply to avoid static shocks that

could damage components and yourself! Now, let's identify the power supply.


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Locating the power supply is quite easy. It is just next to the Hard drive (on the left hand side of it) and is held in

place by 4 size 10 Torx screws. It is in the red rectangle on this picture (remove the screws circled in yellow) and is

only connected to the system by the two power supply connectors.

Let's start with the power supply connector, with the blue and brown wires (neutral+phase, as usual on an alternative

current circuit). The connector is on the bottom right of the power unit.


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Now we turn to the general power supply connector of the motherboard. Once disconnected, the power supply comes

out easily.

Once you have removed the power supply of the iMac, we advise you to carefully indentify the 4 screws that kept it in

place as they have 4 different sizes and threads. Two of them are fixated in aluminum parts and the other two in

plastic parts. Do not mix them up! The following picture helps you to identify each screw and the position of each of

them.

The two screws on the right are located near to the Hard Drive and have metal threads. For the two screws on the left,

the short goes one on top and the long one on the bottom, just like on the picture.

Second step of the removing of the motherboard, disconnect all the connectors that we will identify next.


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To start with, you have to identify all the connectors located on the back side of the motherboard. They are all classic

connectors, except for the audio connector (see next picture, the purple on on the bottom right).

This general view shows you 6 of the screws (out of 8) in green circles and the connectors on the other side that you

will have to remove carefully in order to free the motherboard to pull it up by about an inch in order to disconnect the

power supply cable and the one connected to the IR module.

Before unscrewing the screws holding the motherboard and the two cooling systems, please note the two radiators

fixed by only screw each. (see following picture)

First, you will have to identify all 16 connectors that you will have to remove from the back (in reality the top) of the

motherboard.


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The main cables connected to the different temperature sensors, iSight, Airport, Bluetooth, are on the top of the logic

board. Don't worry, they come out easily. We advise you to tape them to the top of the case so they won't be in your

way when you put the motherboard back in.

On the bottom left, there are three connectors. In red: the IR connector, in yellow: the one for the start-up button,

and last the fan connector in purple. The 8 screws holding the motherboard are circled in green.


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Same view from a different angle.

Still more connectors to remove. On the bottom right, there are two left to remove. Be careful with the one in the pink

rectangle with the chromed top. it is the audio connector. It also hides one of the screws (circled in yellow) that hold

the motherboard.


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You have to remove the connector to access the screw.

Third step of the removing of the motherboard. The hardest part has yet to come. Once the motherboard will be free,

you will still have the last connectors to remove.

Take your Torx screwdriver or key, size 10 and take a look at the 2D plan to locate precisely the 8 screws you have to

remove.


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On this picture, all 8 screws are circled in yellow. As you can see, they are identified by letters, S, M, and L, for Small,

Medium and Large. The screws are located as shown on the next picture. Caution: do not forget the screws located

near to the radiators, the CPU and the Graphics Card on the top right.

IMPORTANT:

Do not forget the connectors shown on the next pictures, don't pull the motherboard out before disconnecting them!

Take your time to check that you didn't forget to remove some connectors such as the infrared

Or even the SATA connector of the Superdrive.


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That SATA connector is not very visible but the cable could be damaged if you were pulling too hard on it.

Step four: Extracting the motherboard.

Once the motherboard is free from its aluminum frame, you have to rotate it slightly in order to free some space on

the other side. This is the second last delicate step since there are still two connectors to remove. Once this delicate

task is over, you'll have direct access to the heart of the beast.

To make things more clear, look at the following pictures.

Pointed here, is the power supply of the smaller logic board. It is accessible but you have to put the logic board back.


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As you can see, once the power supply connectors are removed, the motherboard is completely free. However,

manipulate the whole part carefully. Be especially careful with the radiator pipes, which are quite heavy.

Step 5 : Installing the new CPU.

You have now passed the hardest part of this step by step. For this next step, you don't need any particular skill. You

will only need a paper towel with some alcohol and a little bit of carefulness. For the rest, follow our tour guide.

Here is what the core hardware of your iMac looks like. You can now appreciate the work that Apple put into the

integration of the machine while keeping the design and not infringing on the upgrade possibility. Some really good

work.


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Mounted on an LGA1156 socket, the main interest of this step by step, the Core i5-750 can be replaced very easily. We

can however see the white sticker on the left screw, that if damaged will void the manufacturer warranty. On the top,

we can see the wires connected to the temperature sensor inside.

To remove the cooling system, you will have to follow a diagonal path. Loosen the screws in diagonal (eg. top left, then

bottom right, etc.). Don't forget the screw holding the radiator to the aluminum frame and the PCB (see following

picture).


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This is the last screw you have to remove in order to have access to the socket and the processor. Keep the whole part

in place while unscrewing.

After removing the cooling system, the Core i5-750 is finally visible. We can now proceed to the replacement.


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Be careful to remove all the thermal compound before putting the processor away.

We advise you to replace it with some Arctic Silver thermal compound, one of the best available on the market, in

order to optimize the heat transfer. To clean the sole of the radiator, the best is to use some alcohol on a paper towel.


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In order to free the processor, you just need to press the little lever on the side then to pull it up so the frame comes

up also. Important: no need to remove any screw during this process, the processor comes out without.

Here side by side, the two Core i5 and i7, both compatible with the LGA115x socket.

Last but not least, before putting the radiator back, pour generously some thermal compound on the processor to

ensure a proper heat transfer that contributes to the cooling of the machine.

Very nice performances


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After putting back the iMac together, we tested it to compare the performances of our upgraded computer to other

models. We ran Geekbench 2.1.6 (32 Bits mode) - the only available at the time of the realization of this step by step -

and we found without surprise that our iMac runs close to the similar 2010 model: the 27" iMac running on a Core i7

2.93 GHz, which is still slightly faster, thanks to its faster memory (1333 MHz, while ours is "only" 1066 MHz).

iMac 27" Core i5 configuration.

In our iMac 27" once it is back in one piece and running, the Core i7 processor is immediately detected by the system.

Installing iStatMenu.


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With the same processor and clock speed, our iMac comes in second to the 2010 27" Core i7 2.93 iMac. The reason is

the difference in memory frequency, 1333 MHz against 1066 MHz.

Conclusion

Everything went well and we now have a more powerful computer. Of course, before going through that process, you

have to asses whether it is worth the trouble. A compatible Core i7 processor will cost, depending on the model,

between $250 and $300. If you do it for the pleasure of opening your computer to upgrade it, you'll find it worthy.Otherwise, that's your call. The process will become even cheaper in a few months when the price of theses processors

will drop, but don't wait too long, as the next generation of Intel CPU will probably lead to the disappearance of this

line of processors, and they will become harder to find.

When all the big parts of the computer are out, mostly the motherboard, we can truly appreciate the integration work

that is being done in Cupertino.

By Sylvain ALLAIN and Lionel

Translation by machmeter.

how to replace the core i5 by a core i7 in a 27 imac

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