MBA revA CPU temps, comparing apples to apples

Discussion in 'MacBook Air' started by chopper dave, Jan 1, 2010.

  1. chopper dave macrumors regular

    Jul 23, 2007
    I recently replaced the thermal paste on my MBA revA and want to know if I really made a difference. Of course, I forgot to make a baseline run before I replaced it, so I'd like to compare here.

    I read a lot about people reading CPU temperatures and then taking IR temp readings from the back of their MBA and trying to quantify performance. However, these readings alone are flawed as they don't take into account ambient environment, fan speed, etc.

    From what I remember about heat transfer, the true measure of the thermal paste performance would be the thermal conductivity, or watts/m^2/degC, across the boundary between the die and heat sink. Obviously, everyone's die area is the same. One way to get a constant power across the boundary would be to peg the CPU at 100%. What remains to measure is the temperature drop. We can't really measure it directly, but the MBA has thermocouples at the CPU and on the heat sink, so the difference between them is as good as we can get.

    Would someone mind pegging their CPU at 100%, preferably at full clock speed (mine is 1.6Ghz), until the temperatures equalize with the fan at full speed, and then post results? One thing that could throw results off would be the graphics/northbridge generating heat, but it shouldn't be a big deal if you don't run a game in the background.

    Mine ends up being about 65C for the heat sink and 95C at the CPU.

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