Noise
The 4850 doesn’t consume a lot more power than the HD 3870. Will it be as acoustically discreet?
Excellent news: At idle, the Radeon HD 4850 proved to be the quietest card we tested – it was all but inaudible despite a fan rotation speed of 1490 rpm, thanks to the fan’s size (that rotation speed is only 27% of the maximum speed).
Unfortunately, the same wasn’t true under load, where the noise levels of the HD 3870 are now only a fond memory. The fan ramps up to 3400 rpm, and while not unbearable, it’s definitely audible and a little annoying – subjectively speaking, a little more so than the 9800 GTX +. Admittedly, the single-slot design, with all that that implies (less heat-dissipation area, a thinner fan and the necessity of re-routing the hot air back into the case) is clearly a disadvantage the 4850 has to deal with.