Grease-Off

A test of five thermal greases. – Joe.

SUMMARY: High performing grease can drop CPU temps with very little effort on the part of users; performance differences at low C/Ws can be significant.

I received a sample tube of silver grease from a Korean company called CoolingFlow. This is a non-silver grease. I have not done a grease test recently, so I decided to do a little “grease-off” to test a few of these. Arctic Silver is one of the more well known and I have some of each, so I included these along with a couple that I received with heatsinks, one called “Stars 700” with 25% silver and the other a generic white grease.

I decided to use the Simulated CPU Die Tester for this test, using a Glaciator as the heatsink. I ran the simulator at 98 watts, let it heat up until temps stabilized, then recorded Die and Ambient temps. Delta is the difference between the two and is used for performance comparisons. After each run, I used cleaning fluid to remove all traces of the grease just tested and applied another one.

Overall, I found that the “original” Arctic Silver was thicker than Arctic Silver II. The others were fairly thin under pressure and left a very thin film on the die after removing the heatsink. A thick residual coat inhibits heat transfer.

This are very tight results – the difference between Arctic Silver II and Cooling Flow are minimal and not statistically significant. Silver based Arctic Silver remains a top performer, but just because “silver” is on the label, don’t think it will perform as well as the “tried and true” brands.

Generic white greases will range all over the place and it’s impossible to test all of them, but as a rule they are OK – surely better than nothing! I’ve tried some others and they are all over the place, but generally generic white grease will be off about 1-2 C from the best.

In this test, Cooling Flow did a little better, but the best I can say is it’s competitive with Arctic Silver II – too close to call a winner.

Overall, Arctic Silver II and Cooling Flow will do a good cooling job between your heatsink and CPU. You don’t need a lot – heatsink pressure will compress the grease to a very thin layer, which is what you want.

However, the Cooling Flow reaults are based on a one tube sample; I have asked Cooling Flow for more samples to test and will report on expanded test results within the next two weeks.

Many thanks to CoolingFlow and Nevin at Arctic Silver for providing samples to test. Cooling Flow is not available in the USA at the present time. If you are interested in this product for resale, contact

Young Choi at Cooling Flow.

Email Joe