photonblaster Posted April 21, 2009 Posted April 21, 2009 Noobie to the forum, normally just read all the great info. I searched, did not find any threads on this subject. Couple mil thick gold foil, 1" square should cost less than $10. Conductivity should be about 75% of pure silver, but higher than most silver filled pastes. About the same as Arctic Silver 5. Purer grades should be soft enough to conform to surface imperfections. Silver foil would have higher thermal conductivity but may suffer from increase in thermal impedance at silver-heat shink and silver-cpu interfaces because of oxidation. Is this too crazy even to think about trying? Quote Share this post Link to post Share on other sites More sharing options...
IlijaPlayerP Posted April 21, 2009 Posted April 21, 2009 Noobie to the forum, normally just read all the great info. I searched, did not find any threads on this subject. Couple mil thick gold foil, 1" square should cost less than $10. Conductivity should be about 75% of pure silver, but higher than most silver filled pastes. About the same as Arctic Silver 5. Purer grades should be soft enough to conform to surface imperfections. Silver foil would have higher thermal conductivity but may suffer from increase in thermal impedance at silver-heat shink and silver-cpu interfaces because of oxidation. Is this too crazy even to think about trying? Gold won't transfer heat as good as Silver. It had something to do with the numbers...aluminium was ~300, copper was ~400, silver maybe ~500, diamond was ~900 and gold was between copper and aluminium(I'm not sure about my ~ numbers, corrupted information in my brain, bad sectors ) In other words: Arctic Silver 5 will be better heat transporter than gold. AFAIK gold is better than silver in conductivity, not in thermal transfer. Please anyone correct me if I'm wrong. Quote Share this post Link to post Share on other sites More sharing options...
Crazy_Nate Posted April 21, 2009 Posted April 21, 2009 Give it a try... Do a scientific comparison between the foil and TIM. You might also want to compare no TIM (although, not to be used when there isn't good contact between the heatspreader and the heatsink...) Silver has a lower electrical resistivity than Gold, but it will corrode. It has a higher thermal conductivity than Gold (which is between pure copper and pure aluminum). Quote Share this post Link to post Share on other sites More sharing options...
photonblaster Posted April 21, 2009 Posted April 21, 2009 (edited) By conductivity I meant thermal conductivity. Sorry about that. I did run the numbers comparing thermal conductivity. If pure silver does not oxidize too much, it actually would be the way to go, could give a 25% lower thermal conductivity than Arctic Silver 5. AS5 uses very high thermal conductivity fillers, but still not as good as silver, and there is loss in thermal conductivity since the grains of silver do not make contact enough to match a foil. That's why AS5 and gold foild have about the same thermal conductivity. I was hoping someone might have tried this...I do not have the resources to do it myself. Edited April 21, 2009 by photonblaster Quote Share this post Link to post Share on other sites More sharing options...
IlijaPlayerP Posted April 21, 2009 Posted April 21, 2009 I don't think it will make a big difference. The maximum you can gain over AS5 it would be like 5C with whatever you use. Lap your CPU+Heatsink, use AS5 and you'll get lower temps than the gold foil for sure. Quote Share this post Link to post Share on other sites More sharing options...
photonblaster Posted April 21, 2009 Posted April 21, 2009 I don't think it will make a big difference. The maximum you can gain over AS5 it would be like 5C with whatever you use. Lap your CPU+Heatsink, use AS5 and you'll get lower temps than the gold foil for sure. Based on what? Engnineering calcs say gold will be equal to or better, and silver definitely better unless it tarnishes and messes up the thermal conductivity. Quote Share this post Link to post Share on other sites More sharing options...
Crazy_Nate Posted April 21, 2009 Posted April 21, 2009 The reason why it may not make a large difference is the thickness of the film / TIM. Even with largely varying thermal conductivities, the thickness is very small. Therefore, the thermal resistance won't vary much. Quote Share this post Link to post Share on other sites More sharing options...
IVIYTH0S Posted April 21, 2009 Posted April 21, 2009 i guess if you HAVE the gold foil and DONT have a silver thermal compound then it's better... but just use what you have since the results should be about the same, it wouldn't be worth buying the other. (other for the sake of scientific experimentation) Quote Share this post Link to post Share on other sites More sharing options...
TheConqueror Posted April 21, 2009 Posted April 21, 2009 You do realize that TIM is mostly used to fill the microscopic gaps and valleys in a heatsink and CPU heatsink, right? Gold foil will defeat the purpose Quote Share this post Link to post Share on other sites More sharing options...
photonblaster Posted April 21, 2009 Posted April 21, 2009 You do realize that TIM is mostly used to fill the microscopic gaps and valleys in a heatsink and CPU heatsink, right? Gold foil will defeat the purpose You do realize that I said that more pure grades of gold will conform to these imperfections, right? It will not defeat the purpose. Quote Share this post Link to post Share on other sites More sharing options...
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