Thick Arctic Silver w 3870 is 20C cooler

I was a little disappointed in the low performance I was getting out of my newish ATI 3870. To keep the GPU temp below 95C I had to settle for SVGA resolution and some other low settings. Today I decided to reapply Arctic Silver (AS). When I took the heatsink off, it looked like there was an area where the chip had not made contact with the heat sink because the AS looked smooth and untouched on part of it. Where it had made contact with the heat sink, it was textured because some had stuck to the heatsink and the rest was stuck to the chip. This time I put the AS on thicker and put a thin layer on the heat sink too. No the GPU runs almost 20C cooler in games.

I suspect the heat sink in the m9750 is not designed for the 3870. It is close and will work but another indication it isn't ideal is the GPU ram doesn't get completely covered by the blue thermal pads on the heat sink.

To test my new thick AS strategy. I tried again with a thin application and got a game running high temp of 92C. Then I took it apart and again saw an area where it had not made contact with the heat sink. I put on a thick layer of AS and put it back together and now it has a game running high of 72C.

I understand that a thinner layer of AS is better for getting heat from the GPU to the heat sink but thicker AS with total coverage is much better than thin AS and incomplete coverage.

 

You could try using a copper shim.

 

good thing you dound the issue true thermal paste is not the best but anything is better then nothing

 

I use ICD7 on mine at present, keeps it really cool but is an absolute pain to apply as it's really thick paste.

 

any of you had to replace pads i'm looking to replace min i think i cooked them with sc2 they couct heat barely better then air .....