Ok, I've gotten to play around with my 4850 for an hour or so...
I'm not a professional reviewer and I don't keep an army of benchmarking tools at my disposal. I use shareware fraps and any in-game benchmarking tools if a particular game has them.
Installation was easy. I ran the Catalyst Driver CD that came with it and it set everything up correctly. I searched for an updated driver and the HD 4800 series is not listed on ATI's website yet, nor is it listed on their registration pages, so I'll have to wait to do all of that. I'm coming from an nVidia card, so I'm not familiar with the driver designations that ATI uses. The disc installed driver version 8.5 dated 5/14/2008.
I haven't done any tweaks to the card at all, everything is still set up default, other than changing to my monitor's native resolution.
My setup:
e6420 Core 2 Duo @ 2.13ghz
2GB Corsair XMS RAM
32-bit Vista Home Premium
Sceptre 22" 1680x1050 monitor
I was previously using a Geforce 8600gts 128-bit, 256MB card.
Well, obviously, the 4850 just fucking smokes it out of the water. I've tested it so far on 3 games - Bioshock, The Witcher, and Crysis single player demo (can't find Crysis disc right now).
On my old card, the best I could do on Bioshock was 1280x720, dx10, everything high, and get about 30-35fps. Now at 1680x1050, dx10, everything high, I'm getting anywhere from 60-120fps. The crash scene at the beginning had a few dips down into the high 40's.
I pretty much had the same results with The Witcher. I previously had to run it at 1280x720, mostly medium with a few high settings to get 35-40fps. Now I'm running it at 1680x1050, everything high, 2xAA, 16AF, and getting around 40-60 fps, a few dips into the 30's. If I turn AA off, it never goes below 45fps and pretty much stays in the high 60's.
As for Crysis, I'm not sure how much more optimized the final version is from the demo, but based on the demo, the game kicks this card's ass as expected. I tried a bunch of different resolutions and settings:
It detected that I should run at 1280x720, medium, no AA and I got 50-75 fps.
1280x720 very high, no AA ; 25-35fps
1440x900 very high, no AA; 20-30fps
1440x900 high, no AA; 30-45fps sweet spot for this card, for this particular game, imo
1680x1050 high, no AA; 25-35fps
I think its going to be a great mid-range card, which is what its advertised to be. It'll kick the shit out of anything at 1680x1050 and below, except for Crysis, but we already knew that. Plus it'll only get better with driver updates.
One last point before I go try Company of Heroes; the noise. Its deathly silent. My 8600gts was very quiet, and this card is just as quiet. I did hear the fan kick in a little bit trying the different Crysis settings, but it was still barely audible. I mention the noise because we've read that the Geforce GTX cards are unbelievably loud, and I think it'll be a small bulletpoint in ATI's favor for those who want to crossfire 2 of these cards vs. purchasing a GTX.