Safe graphics card temperatures??

I have an Asus geforce 6600gt and I noticed its temperature is a lot higher than anything else. Normal temperature i.e. when not playing games is about 52-54c. After say 3/4 of an hour playing a game I looked at the temperature and it was 68c. Very quickly it dropped right back down to 55c.
Is this normal?
Id also like to know if anyone knows any official max temperatures of graphics cards in general.
Thanks

 

max temp is 120C before it fries! ur temps are still acceptable, just dont let it go much over 70C