I have been tearing my hair out over the 4850. Great card at a great price, but either noise or heat is killing me.
First card was a Sapphire 4850 with the Zalman VF900-cu. GREAT cooling, but loud and at a certain pitch that drove me MAD!!! Cannot change fan speed. Its going back to Newegg.
Second card was a stock-cooler 4850 from my work, which I can return anytime I want for any reason. 42% fan at idle is fine, but as soon as I go into a game, the 42% is too little and it overheats (90C or more). Even in auto mode, the fan is spinning at 5500+ RPM's and the card is in the low to mid 90C range with excellent ventilation!
So, the Sapphire was too loud (fine for games, but would not slow during 2D due to fixed speed), and the current card with stock cooler will not work (for me, card is fine).
Choices, please help me decide. I want it quiet at idle, but cool for games (even 70C in game in fine).
-Get a stock 4870 - is it cooler and quieter than the 4850?
-Mod the current 4850 (with stock cooler) with the Zalman VF1000 LED (supposed to be silent and still cool the card under load)
-Get an nVidia card (maybe the 9800 GTX+, is it quiet at idle?)
Bonus is if I mod the card I have now and kill it, I can just exchange it (as in, failed Zalman VF1000 install).