This is confusing- you should use the "thinnest" pad that you can get away with. Only enough to make up for any mechanical surface inconsistencies. Thermal Conductivity are the units they use -W/mK, the more common unit is Thermal Resistance which is the inverse of conductivity (just like electronics). You can think of heat sink materials as a series of resistors that are taking the junction temperature though a series of interfaces to ambient. You want the lowest resistance path to give you the lowest temp rise. When you invert their conductivity, you'll get Resistivity with units of mK/W, this is what you want to minimize. Thermal Resistance uses a theta symbol and is usually dimensioned in W/deg C, though W/K would be more correct.
If things are pretty flat, .5mm should be fine, this is .02 inches. I noticed they had some precut units for some common GPU's (3080, etc.) though pricey? A common error people make with thermal pastes of all types is to use too much. "The bigger the blob, the better the job" philosophy of new solderers. All you want to do is fill the tiny gaps and get the two surfaces in intimate contact. Nicely machined and polished surfaces would be the best- but no one but NASA has the dough for that. Good luck. Regards, John M. Wettroth E: j...@mindspring.com M: (919) 349-9875 H: (984) 329-5420 -----Original Message----- From: TriEmbed <triembed-boun...@triembed.org> On Behalf Of Mauricio Tavares via TriEmbed Sent: Thursday, December 14, 2023 10:37 PM To: TriEmbed Discussion <triembed@triembed.org> Subject: [TriEmbed] Conductivity pad thickness I need to replace the gpu card in my desktop and was going to take the opportunity and try to use a conductivity pad instead of the goo. Last time I used it was in heat sinks on my Rpi4, which were bits from what I had used in my 3D printer. It worked I guess, but this time we are talking about GPU and I would like not to half ass it. So I was looking at https://kriticalpads.com/full-sheets and did not realize they sold them by the thickness, with the thicker being supposedly the most conductive. How do I figure out how thick I need? Just the thickest one I can shove in place? I was also thinking about the merit of using them in a laptop, where space is at a premium on a good day. _______________________________________________ Triangle, NC Embedded Interest Group mailing list To post message: TriEmbed@triembed.org List info: http://mail.triembed.org/mailman/listinfo/triembed_triembed.org TriEmbed web site: https://TriEmbed.org To unsubscribe, click link and send a blank message: mailto:unsubscribe-triem...@bitser.net?subject=unsubscribe Searchable email archive available at https://www.mail-archive.com/triembed@triembed.org/ _______________________________________________ Triangle, NC Embedded Interest Group mailing list To post message: TriEmbed@triembed.org List info: http://mail.triembed.org/mailman/listinfo/triembed_triembed.org TriEmbed web site: https://TriEmbed.org To unsubscribe, click link and send a blank message: mailto:unsubscribe-triem...@bitser.net?subject=unsubscribe Searchable email archive available at https://www.mail-archive.com/triembed@triembed.org/
