Hot imac - iStat and smcfancontrol give different temps.

Discussion in 'iMac' started by gingeral, Sep 5, 2010.

  1. gingeral macrumors newbie

    Sep 5, 2010
    Hi i have a 2008 imac and recently replaced the hard drive (HD). During the research process i found this was a common problem. This time i wanted to be able to keep the HD cooler so i downloaded smcfancontrol, i also downloaded iStat to monitor the temperature of various hardware in the iMac.

    My problem is that the software have vastly different readings e.g. with imac basically idle smc fan control says my HD is 30C whereas iStat says it is 43C this is a big difference. I don't want to run the fans harder than necessary or let my HD heat up too much.

    Thankyou for any advice you can give.

    p.s. This is my first post so sorry if i've not done everything correctly.
  2. Spike88 macrumors 6502a

    Jan 25, 2010
    To validate the variance, do ensure one is comparing the same "temp sensor" within each program. For example, Internal HD compared to Internal DVD, compared to CPU Heatsink, compared to GPU Heatsink, etc. etc.

    Here's the different temps for my iMac 21.5". Notice its many different temp sensors. Your iMac has different temp sensors as well. When comparing, I focus on the temp sensors above 55-60C range. IMO, above 65C is getting way "too hot".

    Hope this helps...


  3. gingeral thread starter macrumors newbie

    Sep 5, 2010
    Thanks for your quick response Spike88 but i'm still not sure about the readings.

    I think i'm measuring the same temp sensors: One is labeled "HD: My Mac" and the other is labeled "HDD". I'm assuming that these are from the same sensor as they seem to measure the same device ie. the hard drive. I also have "HD Bay" but that measures the same as "HD: My Mac" +/- 1C. The temps do sometimes get to be around the 65C mark. The "Power Supply" temp is always higher than everything else but my research says this is normal.

    Thanks again :)

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