Oh yeah, it's not really that high because my computers been ripping music and a DVD for a few hours. 256 must be the max that it can go, going on an 8-Bit scale I assume. I found it funny anyway.
My 7800GT has 115C listed as the max temp in the display box, but I've never gotten over 45. Tends to get a bit unresponsive around there. Sadly, I think the stock heatsink works better than the Arctic Cooler 5 I bought. Yes it's silent but I don't think it moves enough air to keep the chip cool clocked as high as I am.
HOLY CRAP that's hot! It must be the max temp, else your card would be fried by now for sure! my card usually sits around 35-45 degrees celcius (the old 8500 LE needs to be put to rest )