R5 Thermal Mod, take 2

Pretty much the same idea as the previous attempt, but with graphite sheets to conduct heat better (I’m using Panasonic PGS sheets). This is 100% not recommended because the graphite sheets are conductive, and are more likely to cause damage.

Published by Yifan Gu

aka. Frank, aka. 顾屹凡

4 thoughts on “R5 Thermal Mod, take 2

  1. Hi Gu,
    I don’t a combination of graphite + silicon thermal pad would improve anything. There is air bags between the pad. And a combination of silicon pad/graphite pad/metal is worse than silicon pad/metal because of air bags in my opinion.
    From my observation, I think you are using the bad kind of silicon thermal pad, 2-6 W/mK.
    The best silicon thermal pad is about 17W/mK of Alphacool or Fujipoly but they are expensive. There are some reasonable thermal pad choice at 12-14W/mK. Some of them could be purchased in China. For example: € 6,27 5%OFF | Thermalright ODYSSEY Thermal Pad , Non-Conductive GPU Card Water Cooling Thermal Mat 12.8W/mk 85x45mm 0.5mm/1.0mm/1.5mm/2.0mm
    https://a.aliexpress.com/_mK4wlY1
    The 14W/mK version of Alphacool is reasonable cheap as well.

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    1. The graphite sheet I added is not for transferring heat in the z axis but in the x-y plane. The graphite sheet you see in pic 1 and 2 is one continuous sheet. The purpose of that is to spread the heat along the sheet, therefore bypassing the relatively thermally inconductive PCB.
      About the thermal pad. I estimate that the CPU is probably 10 watts at maximum, and I’m using thermal pad with heat conductivity of 6W/mK. Assuming we want half of that heat removed by the thermal mod, 2mm of total thickness of thermal pads (that is, the 1mm between CPU and graphite sheet, and 1mm between the graphite sheet and the enclosure), and 20mm x 20mm of contact area, we get 5W / (6W/(m*K) * (20mm)^2 / 2mm) = 4.167K of temperature difference, which is not that good, but also not that bad. I think using better thermal pads will definitely help, but it won’t actually make that much of a difference.
      I think the limitation now is really the plastic outer shell, and the lack of way to remove heat from it without a fan.

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