Question I5 2310 High Temperatures

[greyfox882002]

I built a PC out of my left over parts for my parents.
I'm home on vacation and discovered that the CPU runs very hot both in idle (45-50) and under load (90+)
The results were similar across a wide range of software.

I thought it was the stock intel cooler, so I bought a gammax 400 and replaced it.
This didn't seem to make any actual difference to the temperature reported.

I have tried the common suggestions already:

1. air flow is fine, I even tested with the side panel completely off (no difference)
2. yes I cleaned off the old thermal paste before I applied the new one (I used the appropriate amount)
3. yes the cooler is secure, all 4 push pins 'clicked' and will not go any further
4. I tested on a completely fresh install of windows, so there shouldn't be any background software issues

At this point, I'm starting to suspect its either a hardware failure from the old CPU or the temperature sensor is inaccurate.
Has anyone else had this problem, any suggestions for what tests or experiments I can run to fix or better diagnose the problem?

 

[clutchc]

Are those BIOS core temps or Win core temps? If the latter, what are you using to read them? Do you know the history of the i5-2310?