Need help with CPU temps!!!

[may1]

I've been getting some truly worrying temp record on my old CPU I gave to a friend.
So, IDLE temp is above 50℃ , MAX TEMP under prime 95 doesn't exceed above 65.

Buuuuut, this is the dynamic result of prime 95 testing:

Is this indicative of a faulty CPU?

The CPU is Piix4 955, and cooler is arctic freeezer 7 pro.

 

[InvalidError]

The idle temp is high-ish but 65C max load temp is not too bad.

The HSF mounting or thermal paste application might not be quite right and impeding optimal heat transfer.

 

[may1]

The idle temp is high-ish but 65C max load temp is not too bad.

The HSF mounting or thermal paste application might not be quite right and impeding optimal heat transfer.

But would an incorrectly applied paste/HSF mounting cause the problem?

My concern are 2 things -
1. Unusually high idle temp - roughly 30 degrees above ambient
2. Absurd fluctuation of temp while running prime 95. Regularly oscillating between circa 50 - 65 C. You can see that the graph is pretty much a sin/cos graph. A standard prime 95 stress test would yield something similar to a logarithmic graph like this (I tried with my own PC)

 

[InvalidError]

But would an incorrectly applied paste/HSF mounting cause the problem?

Oscillating or wildly fluctuating CPU temperature usually is a good hint that contact between the heatsink and CPU is compromised in some way.

If the heatsink barely heats up when under load, that's one more reason to think you have a heatsink mount/paste issue.