The only thing lacking in the HD 4870 atm are good official drivers for the card. Its really hit and miss right now depending on the game, some games fly while others like mass effect are slower than my overclocked 9800GTX and then there are a couple of games with graphical glitches (ME and Penumbra)
due to improper drivers.
Since Mass Effect is my favorite game I have put my 9800GTX back in for the time being so I can play the game with 2XAA and still get great frame rates. I did notice a few guys talking about some new beta drivers for the G92 series that supposedly boosted FPS and of course I was skeptical of this so I had to try them. I have to say that nvidia can put some damn fine drivers together because this card is running even better than the last time that I used it with the 175.16.
I did some rough benching between the two cards with the HD4870 at 880core 4400mem and the 9800GTX at 840core 2100shader and 2500mem.
Here is what I found-all games maxed at 1680X1050 with Vsync+tripple buffering.
-HD 4870 4XAA+supersampling always at 60fps even in dense foilage.-Awesome!
-9800GTX 4XAA-No transparency AA 47-52fps in the dense foilage-pretty damn good but transparency AA kills it.
-HD 4870 No AA-for the most part the game is around an average of 15fps slower than the 9800GTX, the first level before the citadel would often run in the 45 fps range compared to the 9800GTX with 2XAA running mostly at 60fps. Plus the visual quality on the HD 4870 is washed out by comparison. (Now keep in mind that the HD 4870 is running on drivers intended for the 3870 card.)
-9800GTX pinned at 60fps through the first level with the exeption of 2 places which dip to 52fps for a very short period. I noticed this game is a lot faster now on the 9800GTX with these new drivers.
-HD 4870 pinned at 60fps with only one dip to 58fps in the first level.
-9800GTX 52 FPS when you first exit the underground in the first of the game and then crawls up to 60fps- only dips down to 52fps when looking at the guys around the camp fire in the first village. Again, drivers really really helped this game.
-HD 4870 60fps when you exit the underground and never seems to dip under it.
The Witcher 9800GTX
-(the game will only detect 2XAA and will not work when AA is forced in driver
) This one really suprised me. The 9800GTX was running this game at 52-54fps in the first part of the New Quest mission compared to being in the low 40's with dips to 25fps on the older drivers. This time the lowest dip was only 35fps. I have to say I am really impressed.
The Witcher HD 4870
-Its really to close to call, both cards seem to get identical results as the HD 4870 had the same low dip at 35fps and ran at 52-54fps for the most part.
The HD 4870 did have a great lead over the 9800GTX in the Witcher prior to these new drivers that I tested. I am pretty sure though that once the HD 4870 gets official drivers it will once again come out on top in this game though.
Thats just a short review and as you can see I own both cards so I am anything but biased and a fanboy. The HD 4870 really has a ton of potential, its just up to ATI to bring it out with good optimized drivers and I hope they can do the job.