Hi GOG hardware enthusiasts! I need to change a CPU and since I really want to do it right the first time I want to ask you how do you apply the thermal compound onto the CPU? It's not a boxed cpu, nor the heatsink is new, so no pre-applied paste or instructions. On youtube and thru some friends I got these 5 methods (the thermal paste is in a syringe):

1. Apply a green bean quantity of the paste in center of the CPU and stretch it out with finger;
2. Apply a green bean quantity of the paste in center of the CPU and stretch it out with a credit card;
3. Do 1 or 2 but before to lock the heatsink to the motherboard, twist left and right the heatsink to stretch further the paste;
4. Apply a green bean quantity of the paste in center of the CPU and just drop the heatsink on top and press it;
5. Do 4, but instead of green bean quantity apply 1 centimeter line in the center of the CPU;

To me 4 or 5 seems most reasonable from the physics point of view, because that way the thermal compound have to be equally spread across the surface of the CPU/heatsink, but is it so on practice? Does it not spread on some parts of the periphery of the surface?

From your practice of replacing CPUs which method is the best?

I always put a grain of rice size right in the middle of the cpu and then let the cooler flatten it out when you put it on.

I tried before spreading it on cpu and noticed I lost cooling and got more heat and the grain of rice method works wonders and gotten better temps. Remember all the heat is in the center of the CPU and not the ends of it.

A lot of those tech guys like linus and others recommend the rice grain size

https://www.youtube.com/watch?v=r2MEAnZ3swQ


Cooked grain of rice size try it and thank me later :)

that reminds me I needs to re apply my thermal paste next month.

I've done this a couple of times in the past, and it's mostly been 4. You put a reasonable sized dot in the center of the CPU, then drop the heatsink on it and slowly pivot it around a couple of times if possible to ensure that pressure has spread the thermal paste evenly.

Pre-applied paste (on GPUs for example) is usually set by machines in thin parallel lines (at least from what I've seen so far) and usually does a worse job of covering the entire GPU/CPU surface than manual application will.

Grain of rice, isn't it small, or may be we mean a different type of rice :)

Another question if it's not good what is the best way to check and see that I need to redo the procedure? I don't have experience with this particular CPU so I can only see it temperatures over the specification what is considered a problem +20% over the nominal, because when it reaches the max it should restart I guess?
A friend suggest to do it once and remove the heatsink to see if the print has any holes, but I don't think this a a good suggestion, because it might not show well and I have like half the syringe from this expansive paste and don't want to waste it :)

I would say Use the pea size method you use a bit more but it is sure to cover what needs to be covered on the CPU Heat plate, Cause I been using the cooked grain rice method for 7 years on cpu's like the AMD 1090T, AMD FX 8350, Intel i7 3770k , and AMD 7890K And never had an issue yet on heating plus I had a decent cooler attached.

Oh and here Take a VERY Close look at logan doing the pea method with a clear plastic to show you how the method works, I tell others to do this and it works 100% of the time.

https://www.youtube.com/watch?v=-hNgFNH7zhQ

Go to 1:45

Apply small quantity at center.
Covering it may trap heat (like green house effect.

As others have mentioned you want to use a pretty small quantity of thermal paste (the grain of rice size suggestion is good). Keep in mind that the purpose of thermal paste is to have just enough to fill in all the tiny irregularities in the metal surfaces of the CPU and heatsink, not to have a pad of thermal paste sitting between them. The method of application I personally use is a line down the center of the CPU about 1 mm wide (at least for modern Intel CPUs you want to position the arrow in the corner of the CPU to the lower left, then apply the thermal paste as a vertical line). This is because the arrangement of the actual cores under the metal covering is actually like a rectangle down the center of the square metal heat spreader, and getting good thermal paste coverage right over the cores is much more important than trying to cover the entire heat spreader. Once you have applied the thermal paste do not try to spread it out. Place the heatsink directly down on the CPU, then gentle rotate it left and right (only around 10 degrees in either direction) while applying pressure to both spread out the thermal paste and force it into all the tiny surface irregularities I previously mentioned. After that you just need to finish anchoring the heatsink and you're done.

Back in the old Pentium days I was running my PC for weeks, probably months, before the techs discovered during an unrelated check-up, that the heat sink was half-detached from the CPU, sort of just hanging by 20% of its surface, and it was mostly a pocket of air between the heat sink and the CPU itself. No problems with the running, except for a sudden restart or two during the summer days, but that might have been down to the failing voltage rails in the PSU, which I was replacing.

I think I have done that more than thousand times. I have a special razor. I take the paste with that razor and apply it on the cpu like you would put chococream on your bread. But in smallest quantity as possible. I dont know about beans :) .

in your options, i think 4 is the worst. Your aim is to increase the heat transfer which is proportional to the area between. When you press like that you are leaving that area to luck which will always worse than what you would do yourself. So 2nd option seems best to me.



EDIT: The actual formula for heat transfer is q = -kAdT/dx where q is heat transfer and A is area between.

Arctic Silver's page has quite en extensive 'Instructions' section.

As far as my experience is concerned - I used method 2.

All this thread did was make me hungry.
Now... rice, beans or peas with my steak?

4. Apply a green bean quantity of the paste in center of the CPU

I wouldn't "drop" the heatsink on it, though :P

Easily the most nerve wracking pain in the ass part for me back when I built my first PC in 2012. Screwed it up the first time and got some on the green circuit board. Freaked out as I thought I had just trashed my CPU, but the gog community reassured me it was fine. Cleaned it off and then got it right on the second try.