Powercolor Radeon HD 3870 512 mb GDDR4

Hi there..
I recently bought Powercolor Radeon HD 3870 with 512 mb GDDR4 and ZEROtherm cooling system on it.
I have few questions about its temperature.
While playing Call of Duty 4 i have normal temperatures round 60 max 70 Celsius. But while playing Grand theft auto IV temperature is round 75 - 85 degrease of celsius.
Is that normal bcs temperature is really high although i know GPU always has high temperatures but 85 (i also had 90 once :S) is really high temp for GPU if you ask me..
Any help would be really apreciated.

My other parts are:
Gigabyte EP45T - Extreme (motherboard)
Intel Core2 Quad Q9550 (running at 3,1 ghz)
2 GB of Kingmax DDR3
600 W power suply
320 GB HDD


help apreciated
thnx again.

im not so into those english or american sleng bcs im from Croatia..so what CCC means?
im thinking to put 3870 into crossfire with another one.
So can you explain me how to tweak rpm of cooler
tnx alot