Motherboard Replacement - Advice On Proper Cooling Supplies And Directions

Hello people. I contemplated where to post this since it applies to modding, cooling and this section but I chose this one because it is closer to owners of my model of Dell laptop - Latitude E6420.

I am in the process of soon ordering replacement motherboard due to problem I described here and need advice of cooling experts and owners of Latitudes.

I have disassembled heat sink with vent and CPU. Here are the pictures of everything.
According to 3rd picture from above, you will see the left uppermost chip (PCH) that has thermal pad on it. It probably has pad instead of thermal paste because it heats less compared to CPU and GPU.

Not smart question: should I transfer old thermal pad to motherboard with on same chip or buy new thermal pad like this one? If anyone knows of reliable thermal pad to suggest, it would be good to hear.

Other pictures display chips and heat sink with white TIM on them. I don't know which exactly is it and not sure whether it is high quality but I would like to know, whether I should buy special solution for old TIM removal or buy 99% isopropyl alcohol or find something at home to take care of old TIM.

About TIM itself. I heard good things about Arctic Silver 5 but it is rumored to have been lessened in quality. I also heard about Ceramique 2 which was recommended by one owner of Latitude E6420 to be put on GPU. That guy also recommended getting shims for better cooling in this link where listing has ended but if you scroll down, you will see picture and description. Since listing is no longer actual, can you recommend alternative, which size of shims get and generally guide through process?

Thank you beforehand for your time.

 

For the PCH and GPU you can reuse the old thermal pads... they will more or less perform exactly as they did before you replace the motherboard.

For the CPU, I usually use a spudge to scrape off the bulk of the old paste, and then rubbing alcohol to remove the rest. AS5 is fine, and Ceramique 2 should be fine too.

If you want to improve the cooling on the GPU you will want to use the shims and get rid of the pad entirely. Just make sure your shims are the right thickness, or the cooling performance could decrease if your heatsink is seated poorly. It is slightly better to have shims that are too thin as opposed to shims that are too thick as your paste can take up a small amount of the slack.

 

Let me clarify that GPU on motherboard did not use thermal pad, it was just thermal compound though a guy from Arctic Silver told me to use thermal pad still, just to make sure it is new thermal pad. But he also said if I want to use thermal compound only, I should perform a test with a thin piece of paper by putting it on GPU, tightening heatsink and try to see if I can pull paper out. If I can't pull out paper, then it made decent contact.

About removing thermal grease, what is alternative tool for spudge. I heard it is better to use isopropyl than rubbing alcohol, is this true? Arctic Silver offer special cleaners but I wonder if it makes difference.

So if PCH chip uses thermal pad and GPU chip uses thermal pad or shims, won't that make both sides of heatsink elevated a little and leave CPU chip below? Should I use shims or thermal pad to level it out?

 

At least on the E6420s with dGPU that I've seen it's been a pad... but the paper test is a good test; if you indeed can't pull out the paper, you should just use paste.

There's no practical difference between using isopropyl and rubbing alcohol. The spudge is just used to scrape off the really big chunks if there are any. Just use anything hard but not hard enough to scratch the heatsink or die.

If you've done your shimming right, the heatsink should rest perfectly level on the GPU shim and CPU die.

 

That assuming I tight heatsink screws to the max?

I don't have isopropyl or rubbing alcohol in house. What else can I use?

I don't think I can find shims matching exact dimensions of my CPU or GPU dies. Will I have to buy general size and then cut them according to dies dimensions? And how do I find die dimension of CPU and GPU?

 

I mean, yeah, tighten then, but don't go crazy or anything.

Just scrape or rub the stuff off 'til it's all gone...

It's not the area that matters, it's the thickness. The area just needs to be approximate, or even a bit bigger. You should NOT be shimming both of them, only the one that has a gap between it and the bare heatsink (presumably the GPU). You need to find shims that are the right thickness such that the heatsink sits level on the CPU and GPU. Honestly, I don't know a good way to do this other than trial and error, and it may vary slightly between individual laptops.

 

I use bounty/paper towel + alcohol . Alcohol is in pharmacy/drug store /99c store and cost around a cup of coffee , unless you live in some country that prohibit any alcohol.