I'm building a new gaming rig and I don't know what to choose between the 8800GTS 640 and the HD 2900XT.The other components are: Intel Core 2 Duo E6750,2GB Corsair dual channel 800mhz,Gigabyte P35-DS3
Check the AMD/ATI website for PSU recommendations for the HD2900XT. That would be a good place to start. For myself, I selected a PC P&C Silencer 750 Quad for it's dual 6/8 pin PCIE power connectors and single 60A +12V rail.
If I was you I'd nab a 8800 GTS....g92 should be out around late november/october...this way if you grab a EVGA card you can use the Step up program to get a g92...you just have to slap on some extra cash for it. that is if you have the cash to do this...
Well, it is either as fast, or faster than GeForce 8800 GTS 640MB in most cases, but it has performance issues with such games as S.T.A.L.K.E.R.: Shadow of Chernobyl , Neverwinter Nights 2 , Gothic 3 and probably some other. At some point those problems are going to be solved, but when – we do not know. So, performance-wise, ATI Radeon HD 2900 XT is a good solution.
In addition, AMD’s partners will include four free games with each Radeon HD 2900 XT graphics board: Half-Life 2: Episode 2 , Day of Defeat: Source , Team Fortress 2 and Portal . This increases overall value of the product to a gamer.
However, with sufficient performance and free games come power consumption of 161W as well as very noisy cooling system (at least, in case of our board) in addition to imperfect drivers, which, for example, do not allow to enable FSAA with edge-detect filter, something, which is projected to provide high image quality amid minimal performance drop. As a consequence of such driver limitation of the Radeon HD 2000, Nvidia’s GeForce 8800 can claim better image quality, as its CSAA works without an issue.
To summarize, the $399 Radeon HD 2900 XT is a feature rich, DX 10 class graphics card that competes relatively well with a standard GeForce 8800 GTS in many aspects, except power consumption. We wished it was more, but a company can pull only so many Radeon 9700-type launches out of their hat. Over time, the Radeon HD 2900 XT is likely to become a somewhat stronger product due to more finely tuned drivers and continued tweaks made to TSMC's manufacturing process, but for now it is what it is. And who knows what ATI has in store over the next few months. If I was a betting man, I'd say a new high-end GPU manufactured at 65nm will arrive sooner rather than later.
Maybe that's a lot to digest, but the bottom line is that R600 is not perfect nor is it a failure. The HD 2900 XT competes well with the 640MB 8800 GTS, though the 8800 GTS 320MB does have a price/performance advantage over both in all but the highest resolutions and AA settings under most current games. There are features we like about the hardware and we would love to see exploited. There is potential there, especially for Xbox 360 ports, to really shine... though console ports are often looked down upon in the PC market, particularly if they come late and offer little new to the platform.
Ultimately, though, we can't overlook the fact that AMD built a GPU with 700M transistors that has 320 stream processor ALUs and a 512-bit memory interface, yet it just matches or slightly exceeds the real-world performance of the GeForce 8800 GTS. The GTS is an Nvidia G80 with 25% of its shader core disabled and only 60% of the memory bandwidth of the Radeon HD 2900 XT. That's gotta be a little embarrassing. At the same time, the Radeon HD 2900 XT draws quite a bit more power under load than the full-on GeForce 8800 GTX, and it needs a relatively noisy cooler to keep it in check. If you ask folks at AMD why they didn't aim for the performance crown with a faster version of the R600, they won't say it outright, but they will hint that leakage with this GPU on TSMC's 80HS fab process was a problem. All of the telltale signs are certainly there.
It is what it is, and the HD 2900 XT performance wise ended up in the lower to mid part of the high-end segment. Sometimes it has a hard time keeping up with a 320MB 8800 GTS, and in other scenarios we see performance close or equal to the GeForce 8800 GTX. Now that would be weird if we all had to pay 600 USD/EUR for it. AMD knows this, and knows it very well. This is why, and honestly this is fantastic, the product is launched at a 399 MSRP. Now I have been talking with a lot of board partners already and here in Europe the product will launch at 350 EUR; and that's just golden.
So we need to leave the uber-power-frag-meister-performance idea behind us and mentally position the product where it is and compare it with the money you have to pay for it. For your mental picture; performance wise I'd say GeForce 8800 GTS 640 MB is a good comparative product (performance wise). Then the opinion will change as you'll receive absolutely a lot of bang for your bucks here. At 350 EUR you'll have a good performing DirectX 10 compatible product, new programmable tessellation unit. It comes with 512 megs of memory. It comes with a state of the art memory controller, offers HDCP straight out of the box, all cards have HDMI connectivity with support for sound and if that alone is not enough, you receive a Valve game-bundle with some very hip titles in there for free. So yeah, you really can't go wrong there.