Why is my CPU so hot?

[Anchundan]

I recently made a visit to UK, and picked up an AMD64 X2 4200 (socket 939). I used to have the 3500 Newcastle.

My idle temperatures at stock are 51°C (core 0) and 47°C (core 1) using Core Temp.
After 2 hours of Prime95, my temperatures reach 66°C. I'm sure the S939 X2 4200 are supposed to run lower than this.

I'm not quite sure why it's so hot. I used Arctic Silver 5, from a tube I bought in 2005 (and it's been lying on it's side as didn't know you were supposed to store it upright). I'm also using a Zalman CNPS7000B-Cu CPU cooler, with the fan on maximum. Also, when I cleaned the old AS5 off the heatsink, I couldn't find any solvent, so had to use Chinese vodka (62% alcohol) - just can't seem to find any kind of solvent out here.

Do you think the zalman cooler is the problem? Their website does seem to indicate it's good enough for the Athlon 64 X2 though.

What temps should I be getting?

 

[Anchundan]

Thanks for the tips!

I'm on my way back to UK for Christmas, so I'll try to pick up something a little better to clean it with (provided they'll let me back on the plane with it)!

The Chinese vodka's called Baijiu, and is really bad stuff - tastes and smells awful! It was actually a guy in a PC shop out here who told me to use it, I'd searched for hours for something better, but couldn't find anything.