Thermal paste - how much is too much

[maflynn]

I'm sure this subject has been bantered around a lot.

My issue/question is this: I was putting on a noctua nh-d14 cpu cooler and in my test fit, I found that the thermal paste, using the pea sized dollap in the middle method failed to evenly spread to the entire cpu die. I opted to clean the puppy off and then use the razor blade method.

It may have been on a bit thicker then I think I might want but I was having trouble getting an even application in such tight working area. The middle may have had a bit more, but the everywhere else, it was razor thin. Now that its after the fact, I'm second guessing.

This leads me to my question how much is too much. While my temps are much better then the corsair H50, I wonder if picking up some new thermal paste and redoing it is worth the effort.

I'm seeing idle temps of 38-41c (ambient temps in the 25-30c range) and load temps in the low 60s, via prime95

What if I cleaned everything off and then put the thermal paste on the DH-14 instead of the cpu die. I'll have more elbow room to ensure a thin even coverage. What risks/issues could I face by putting in on the cooler first, as opposed to the more accepted method of on the cpu.

 

[OvrClkr]

To be honest the only method that has worked flawless for me in the past 15 years is this one.

Small pea sized dab

Spread evenly with an old debit / cc card

Done..

I have seen users apply a small dab of AS5 in the middle of the cooler and slapping it down onto the CPU or vice versa. My suggestion is that you DO NOT do it that way as it can pour onto the board if too much is applied. As long as you make sure that the cooler or CPU has a thin layer spread evenly you should be good to go. I normally paste the cooler and to this date if anything its performed better than pasting the actual CPU, it's easier to spread IMO.

This was the outcome after installing the cooler...

x2 550 (3.9Ghz) @ 70F ambient
http://s683.photobucket.com/albums/vv199/OvrClkr/?action=view&current=39Ghz-2.flv

 

[17seconds]

Zalman makes a thermal paste that comes with a small brush (apparently the reviews are quite good). The applicator is similar to how you would use "White Out" on paper. I don't know why other manufacturers have not adopted that method, but it seems like a much more precise way to apply paste.

 

[maflynn]

I used SIIG (something I picked up at microcenter) which has a brush. That product is a clone of AS5, where as I want to something like MX-3.

I think doing it on the cooler makes a lot of sense, one concern I had was that the cooler plate is larger then the cpu. What will happen to the thermal paste that doesn't meet up with the cpu die?

I'm happy with the performance of the cooler now, but I think being anal retentive, I want to get the thermal paste "perfect" and so I'll end up re-doing it. I'll try the credit card approach that seems to make a lot of sense.

 

[17seconds]

Good point, the Corsair A70 heatsink doesn't even have a cooler plate, so you need to apply paste directly to the CPU so that it doesn't overflow.

 

[maflynn]

Best answer selected by maflynn.

 

[OvrClkr]

I used SIIG (something I picked up at microcenter) which has a brush. That product is a clone of AS5, where as I want to something like MX-3.

I think doing it on the cooler makes a lot of sense, one concern I had was that the cooler plate is larger then the cpu. What will happen to the thermal paste that doesn't meet up with the cpu die?

I'm happy with the performance of the cooler now, but I think being anal retentive, I want to get the thermal paste "perfect" and so I'll end up re-doing it. I'll try the credit card approach that seems to make a lot of sense.

I find MX-2 and MX-3 to be the best paste for the money, the problem with AS5 is the fact that it just takes to long to cure and it can harm the board if you leave any traces.

What will happen to the thermal paste that doesn't meet up with the cpu die?

Nothing, as long as you apply a thin layer it will eventually dry up in those spots where it's not touching the CPU.

Keep us posted with the results