@Topic: I think Scawen has confirmed that this bug is now already fixed in his version.
50°C is OK, 84°C is a bit high but still on the border of being OK, at > 90°C the chance that your card won't survive the next month is already very very high. At 120°C (which is for whatever reason listed as the GPU shutdown limit) your card is toast / broken / FUBAR. Not maybe, definitely.
I speak of experience, also with 6600GT cards, which are notorious for overheating with the stock cooler. If your card ever reaches > 90°C, you should consider getting an replacement cooler, at least if you plan to keep your card for a bit longer.
Every gpu can survive 100C. (my own experience, tested on 2 x1950pro's and 6800gt) Yes, @ 90C you should think of buying a replacement cooler. But at first you should check whether the fan/radiator isn't full of dust. My sapphire x1950pro was in so bad condition, that with fan @ 100% I still got 100c+ when playing racedriver grid. I cleaned it up and now it won't go over 70c at ~70% fan speed