Is the temperature you refer to your idle temperature or your temperature under full load? I have a 900 as well, and my idle temp is usually around 5 degrees celsius above my system temp. Right now my system temp is 28, and my cpu temp is 34. under a full load, my cpu has gotten as hot as 55, but not often. The only time I have seen it get this hot, is when I had the computer inside the cpu compartment in my desk. When I have it outside where the air is cooler, it normally doesn't get hotter than 45 celsius. I have the fan that came with the cpu from AMD, and have tried other fans, but didn't get any better performance from a Global-WIN Fop32. As long as you have a decent fan, and are using thermal paste, you should have that area pretty well covered. Case ventilation can be a big factor too. If you have poor ventilation, your system temp will stay high, and it is hard for any fan to do a good job when trying to cool with hot air. But, I guess to answer your question directly, I did not have any problems when my 900 hit 55 celsius. It does seem a little warm, but athlons are known to run rather hot. As long as it did not get any hotter than that, I wouldn't worry too much, as long as it was stable.