Upgraded CPU: Too hot or not?

So I swapped out my Core 2 Duo E6700 for a Core 2 Quad Q9550 using the same cooler.

Core 0 runs significantly hotter than the other cores (10*C hotter than the coolest core)

During stress testing, it peaks at 64c. Is that bad or okay?
http://postimg.org/image/hb20djh8j/

 

The case and CPU cooler are from an OEM desktop. Better than the intel cooler but not a great cooler.
64 C is a bit warm, but if it reaches that under stress testing, it should be ok. Stress testing tends to be a higher load on a CPU than normal usage.
It doesn't keep rising. It actually peaks at 64C and once the CPU case warms up the motherboard
raises the fan speed and it goes down to 61-62C. So is it okay?


Thanks