Slashdot Mirror
The Thermal Paste Revolution
arhines writes "ZZZ is running an article about an interesting new thermal paste which surpasses even solder in thermal conductance by 33 percent. If this paste makes it to the market sometime soon, we'll all surely be thinking about putting it in our boxes. In fact, if use of the paste becomes commonplace, it may even give the semiconductor industry a little speed boost."
" Lots of OEM or low end cooling setups use either a thermal interface pad (TIM) or that white goop you get at radio shack. The fact is that neither of those does a great job of transferring heat from the processor to the heatsink. While they work ok, they don't exactly assist Moore's law in fulfilling itself by limiting clock speeds with heat." Actually, that's hardly true at all. RS's compound has been found to be one of the best out there. Just take a look at some reviews that include it.
I got a +5, Troll
They seem to have just duplicated the inventor's press release - the article doesn't contain any independent evaluation of the substance whatsoever.
I think you misunderstood the statement. They may have compared the thermal conductance of this material to solder, but they're not looking to replace solder. Solder is made up of metals, so it's naturally a good conductor. But metal doesn't spread very well over microscopic cracks -- and no, you can't fill in the cracks with solder, because the metal will contract when it cools and be useless as a thermal paste. You wouldn't want to use a thermal paste as a solder, because thermal paste typically takes a very, very long time to dry when not exposed (ie: between a cpu and a heatsink).
So it looks like CowboyNeal is saying if this new thermal paste can improve the effectiveness of a heatsink (and fan) by a reasonable amount, manufacturers will be able to push their clock speeds a little higher.
The Thermal Paste Revolution
Oh you bet, it will be like 'before and after', a marking point in history. As in; I remember back in the days, before the revolution.
Remember these days people, its one of those great turning points in history and you are part of it.
You know, that's just perfect. Just yesterday I was looking at my Power Macintosh G4 and saying "You know, if there's one thing this computer's missing, it's paste. If only there were some way I could just take paste and smear it all over the inside of this computer."
And now here we are!
Working in a test lab for PCs I encountered one problem with heat conducting paste: Since Intel introduced the mPGA 478 housing for their CPUs the ZIF socket on the mainboard is much smaller than the heatsink above. That means, if the paste between processor and heatsink is too much adhesive it is like the processor is glued to the heatsink and every time you remove the heatsink (e.g. for changing the CPU) you pull out the processor from a closed ZIF socket! Ok, so far the processors survived but I don't think that this is nice anyway.
I have a tube of Arctic Silver 2 (yeah, I'm like two generations behind) but I'm not sure that I really needed it. This dude tried out several non-conventional thermal transfer compounds, including vegemite.(!) When properly applied, there wasn't a huge difference between them. In fact, in the (extremely specific) conditions, the vegemite and toothpaste outperformed the Arctic Silver! (Obviously, you should read the article for details.)
The article's point isn't that you should be using toothpaste; rather, it's that make sure you properly apply whatever thermal compound you do use, and don't expect miracles. No matter how effective your thermal transfer, you've still got to dump the heat somewhere. If you're running close to the edge of thermal failure, there are almost certainly other, much more effective cooling solutions. This new paste is probably a good thing, but don't expect miracles.
Only on Slashdot would you ever see the words "interesting" and "thermal paste" used together.
This may help solve the problem that thermal compound applied badly is worse (in terms of temperature) than none at all.
In a thermal compound we are seeking somethng that:
(1) will conduct heat to the heatsink better than air
(2) will remain inert under extended high temperature exposure
(3) is non toxic (nice seeing as we have to deal with the stuff)
It is difficult for a material to conduct heat better than air if (large or many) air bubbles are present between the two surfaces, trapped by the compound itself.
So we all know how silicone performs, it meets 2 and 3 but there are some issues with 1, mainly because of the air bubble issue.
Carbon black, polyehtylene glycol and ethyl cellulose are both non-hazardous and ethyl cellulose is only mildly hazardous (Material Safety Data Sheets www.merck.co.th, criterion 3 met)
Particulate size is small (should lick the air bubble problem).
Spreadability should be a-ok (ethyl cellulose is a molding compound.
No polymerisation or other chemical reaction should occur (stable mixture, criterion 2 met).
Carbon is a brilliant conductor in this form ( criterion 1 met)
I think it'll work
About 10 years ago I was working on a product that used 200 Amp IGBT's for a traction drive. I spent about a month researching the thermal circuits used to cool these devices.
The conclusion: The best thermal contact is metal to metal. The best way of acheiving this is by "lapping" the contact area's together with a fine abrasive. Once your have done this the application of a minute amount of thermal grease improves conductivity by less than 0.5%. We also discovered that applying more than a fine film or grease significantly decreased the conductivity (10% or more).
Lay off the grease!