I recently upgraded the hard drive in my 3 year old T400 and since then have faced extremely high temperature. According to tpfancontrol, the cpu and gpu were getting up to around 80 degrees C before I forced the fan to spin as fast as possible. What's interesting is that despite the increase in temperature coinciding with the hard drive replacement, hard drive temperatures have been completely normal, according to both sensor readings and touch. I reapplied the thermal grease yesterday (arctic silver), which has caused the cpu temp to drop a few degrees, but nothing significant. For the record, the new hard drive is running at 7200rpm, as compared to the 5400.
Any advice? This machine has treated me well, and I'd love to keep it going.
That is strange. Can you temporarily swap back in the original drive to confirm that there is a correlation between the drive and the high temperatures?
Use "Process Explorer" (free download from microsoft.com) to determine if there are any processes running the CPU up to 100%. If so, you can either kill it or use a program called "Process Lasso" to throttle the processes that are causing the trouble.
I once had an old laptop that had similar issues, and I throttled back the CPU to 75% in the Windows advanced power settings. The performance difference was hardly noticeable at all and the PC ran a lot cooler.