Changing the processor on a LGA775 motherboard

Fig. A

First of all, please read the disclaimer at the bottom of this page.

You should also know this tutorial is intended for the more popular air coolers that normally contain a fan and a radiator, like shown in the image on the right.

Now, with that out of the way, I'd like to explain a few things about the LGA775 motherboard and compliant processors.

Unlike older socket types ( Socket 478 for example ), the LGA 775 motherboard introduced protruding pins instead of the multiple socket holes found in the past ( see fig. 1 ). There are 775 pins, hence the name.

As expected, the compatible processors don’t have multiple pins on them like older processors, instead having just connectors arranged in the same pattern as the pins on the motherboard ( fig. 2 ).

Fig. 2

 

Fig. 1

What will we need for this task? I hear you ask..

1. A LGA775 compatible processor ( mine is a 2.9GHz x86 Intel Pentium Dual-Core );
2. Thermal paste ( I've used MX4 thermal compound - the manufacturing company isn't that important );
   
3. ** A flathead screwdriver ( make sure it hasn’t got a magnetic tip as that can disturb the microcontrollers and sensors on the motherboard );

** An Allen key or Allen wrench can also be used but the screws have springs behind them to keep tension so they probably won’t budge if you don’t use a proper screwdriver. Also, chances are they haven’t been unscrewed in a long time so that’s another argument in the favor of the flathead screwdriver.

I. Removing the old processor.

Let’s start by removing the case of your computer. Whether it’s a tower PC, a desktop PC or even a mini PC you’ll have a couple of screws or just some clips and the front of the case will come right off. That’s the easy part.

Now we see the cooler and radiator. Normally, both come as a single unit ( fig. A ).

Your computer may have a plastic cover that redirects air from the front of the PC to the radiator. After air passes over the processor, it is sucked out by the second fan screwed on the back of the radiator. If your computer has such a cover simply remove it away from the top side as it shouldn't have any clips or screwes holding it in place.

Now we have access to the radiator. It has 4 screws located at its base ( Fig A - 1, 2, 3, 4 ).

Fig. 3

As you can see from the picture attached ( fig. 3 ), there can be stickers on the screws that hold the radiator into place, that means you’ll forfeit your warranty if you break these stickers.

You can also see there is a small spring keeping tension between the screw and the radiator mounts.

Unscrew all four screws bit by bit moving from one to another not to cause strain on the processor beneath this module.

When the radiator becomes loose, try holding it to prevent it from falling on the motherboard or even jump out as it can happen because of the springs.

Take the four screws with the springs and place them somewhere you don't accidentally hit them ( this advice may seem as a no-brainer but, trust me, it happens to the best of us 😃 ).

Now, take the radiator and cooler module off to reveal the processor.

* insert epic soundtrack here *

At this point, the processor is being held into place by a small metallic door ( for the lack of a better term 😊 ) that has a metallic pin on its side ( fig. 4 ). Open the pin then open the tiny door.

 

Fig. 4

Now you can gently take the old processor out. Notice it still has paste on it. Check the state of the old paste to get a clue of the processor’s state. A dry paste will indicate that a change of paste is long overdue.

 

II. Putting the new processor into place.

Fig. 5

Get a new processor in position or just clean the old processor and place it back in.

The processor will only sit in a certain position with the metallic back facing you, as shown in the image on the right ( fig. 5 ).

Use the cuts in the processor’s sides as a guide to how it’s meant to be placed.

Place a coating of thermal paste on the metallic side of the processor, making sure it is just right ( like in the story 😁 ).

If you put too much paste it will spew on the motherboard when you tighten the radiator and cooler module while putting too little will result in an improper cooling of the processor.

That being said it is better to put too much then clean it off than puttin less than enough.

To make sure you put just enough thermal paste use the syringe provided with the tube ( sometimes it arrives in a syringe like in figure 6 - 1 ).

Use the syringe to draw three or four lines on the processor ( depending on how big the nozzle on the syringe is ) or just draw a big Z across it.

Fig. 6

 

Now, use the applicator ( fig. 6 - 2 ) to smear the whole metallic back of the processor with the thermal paste. Try to smear the paste evenly.

Don't rush, as the paste won’t dry up on you like glue does. Also, if you smear the surroundings of the processor or the motherboard, clean the paste off with a soft handkerchief or a tissue.

Now close the tiny metallic door thingy and tighten the clip back in.

Gently, very gently, place the radiator and cooler module on top of the processor. This step is better done with the help of a friend ( it can also help if you’re an octopus ).

The cooler and radiator module should be kept firm into place while the screws are tighten bit by bit. Make sure you don’t tighten one screw all the way up then move to another as that will make the thermal paste to become uneven.

As I’ve said before, tighten the screws bit by bit screwing them clockwise, counter-clockwise or diagonally ( Q:What did he say dear? A:Diagonally. Not into Harry Potter? Ok ).

If you’ve ever tighten a car cylinder head, you’ll know what I mean, just imagine the thermal paste is the head gasket.

The springs will make tightening the radiator a bit awkward but, again, make sure you tighten it well or you’ll have to start over.

Now place the plastic air funnel next to the radiator and close the computer’s case.

Your computer should start right up and boot ( once you put all of the cables in, of course 😁 ).

You're good to go.

If you have any questions, don’t hesitate to ask me in the comment section below.

III. Disclaimer:

You can lose your warranty if you open your computer case and you’ll definitively lose your warranty if you’ll remove the processor radiator. Follow the steps of this tutorial only if your warranty has expired or if you are ok with forfeiting your computer’s warranty.

This tutorial was done to the best of my knowledge and in the best of my intentions but all liability with respect to actions taken or not taken based on the contents of this site is hereby expressly disclaimed.  The content on this posting is provided "as is", no representations are made that the content is error-free.

Under no circumstance I shall be liable to any other Person or Company for any loss of profits, loss of use, or for any damage suffered or costs and expenses incurred by Company or any Person, of any nature or from any cause whatsoever, whether direct, special, incidental or consequential, arising out of or related to the use of this site.

Thank you, Claudiu Radu, C.R.G. 2023.