Corei7 2720QM - 2 cores are >20c higher than others under stress!!


I have a Thinkpad w520 with corei7 2720qm CPU. Recently, i noticed that the temperature on core 2 & 3 are over 20c higher than core 0 & 1 (e.g. core 0&1 were sitting at 70c while 2& 3 were 97c and got throttled) when running wPrime. The temperatures are similar at idle status though (low 50c).

I've cleaned up the fan and it looks fine. I haven't taken off the heat sink to check the thermal paste though.

I'm just wondering is this normal for a quad core cpu? or does this sounds like a CPU problem to you?

Thanks in advance!
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  1. Best answer
    It's normal for a few degrees of difference, but not where half are overheating where the others aren't.

    I'd clean off the CPU and heatsink and apply some higher end thermal paste evenly.
  2. +1 for Twelve

    I have seen it run as much as 10c hotter on a couple cores than on the others but to be 20c I would guess that the thermal paste wasnt spread well creating bubbles where the heat isnt pulled away as effectively. Also try another temperature monitor software like HWMonitor.
  3. Hi Twelve and IntelEnthusias, thanks for your quick response!

    I've tried CPUID-HWMonitor, Realtemp and HWiNFO64, all of them reported similar temperatures. HWiNFO64 showed only the core #3 got throttled as it hit 97c only few seconds after running the stress test (wPrime), while core 0 & 1 were sitting at 70c, and core 2 was low 90s.

    I've been using this laptop for 1.5 years, I'm pretty sure it wasn't like this before as it could always finish wPrime 32M under 10s (I remember the max temperature was like low 80c for all the cores), and now it takes over 11s due to the throttling :pfff: ...

    I didn't modify anything since I bought it ... so maybe the thermal paste got burnt out?
  4. I doubt it got "burnt out". Is there some other cooling path that is blocked or could a bump have loosened the heatsink?

    Either way, redoing the thermal compound would be on my list.
  5. Thanks Twelve! I've called Lenovo and they'll send me a tech on Monday. I'll update the findings.
  6. Alright, you even got someone else to work on it! Nice. :)

  7. Best answer selected by jancc23.
  8. Hi guys, the lenovo tech came this week and reapplied the thermal paste, and it worked ! Now my laptop is back to normal with max temp. range from 76-80 on all the cores when under stress test. The core 3 is not being throttled anymore.

    Thanks so much Twelve and IntelEnthusiast for the insightful suggestions! Hope this post can help others who encounter the similar issue.
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