The Catalyst driver in Windows shows the GPU temperature of my 2600XT. While gaming it reaches 91°C (196 F) and idles at around 45°C (110 F) ! I don't know if these values are to be considered too high. Room temperature is about 19° and I didn't have any artifact or stability issue so far, but on a long-term basis that could change... I didn't believe in these values first, until I measured the exhausted air of the card and got 70-80°... How hot is your card?