TIM: To spread or not to spread?

[Changnoi]

I've noticed that different Thermal Interface Materials have different directions for use. Some call for a small dob in the middle of the heatspreader, other a line across the cores, while still others should be spread evenly over the CPU.

I'm a blob-in-the-middle guy, reasoning that the pressure of the heatsink will spread the material out evenly anyway. Those were the directions that came with my AS-5. Why would that not work with TX-2 (which calls for spreading)?

Could it have something to do with the fact the TX-2 is packaged with the Sunbeam Core Contact Freezer, which contacts the heatpipes directly with the CPU heatspreader, and the TIM easily slips into the cracks between the pipes? If that's the reason then, it would depend on the heatsink rather than the TIM.

What are your thoughts on the issue? Should there be one method for all, or does it depend on the heatsink? Could each TIM really be so different that they require a different application method regardless of heatsink?

 

[gomi]

I tried the small dab in the middle then took off my HSF later and saw that the thermal compound didn't spread out evenly.

After that I have been spreading it thinly over the cpu just for my piece of mind knowing that the entire heat spreader is covered.

 

[AKM880]

Well if the CPU cooler is not concave and is real flat I use the "small dab in the middle and use the HSF to even it out" moethd

 

[plasmastorm]

Laptop cpu's i tend to put a spot in the middle, however on Pc cpu's, GPU's and anything with a large surface area i usually spread it with a piece of card.

If your not sure which will work best for your cpu/cooler combo you can aways try 1 method, remove the heatsink / clean it, then try the other and see what the coverage is like.

 

[hundredislandsboy]

If yo use the "BB-sized dot in the middle" method, the only way to tell is wait a couple of days burning in the TIM and then remove the heatsink to see how effectively it covered the CPU.

With AS5, I prefer to make a small X halfway from the center to edge. I find that this improved my cooling over the BB dop method using an e4500 at 2.93 GHz and Artic Cooling Freezer Pro 7.

 

[wuzy]

Madshrimps.be, [H] and myself have confirmed with various pastes not to spread (with the exception of those liquid metal stuff). This is what you'll find in instruction for your particular thermal paste also.

This is for both IHS and bare die. With bare die I used a tiny half rice grain size.

[EDITED]With the case of direct touch heatpipes you apply the same principal, but with three tiny grain size paste on the heatpipes instead.
The point is not to spread them which creates an uneven surface that can potentially trap micro-bubbles.

 

[4745454b]

I'm a spread guy. I've never met a none flat heatsink, but I don't trust it to evenly spread the TIM across the entire chip. The only way to be sure is to do it yourself.

 

[logainofhades]

I do the dab in the middle myself. Though my cooler is such a pain to install that it always ends up getting spread by the time I am done.

 

[jitpublisher]

I have always done the tiny dab in the middle, apply heatsink 1/8 turn off, twist into place while pressing firmly, lock down heatsink. Never had a coverage problem, never had a heat problem.
However you put it on, the end result is what you are looking for. If the CPU runs without getting hot, you have done a fine job.