The biggest architectural change the GeForce 8800 cards introduce isn't the usual generational move to a smaller manufacturing process--both are 90nm cards like those of the GeForce 7900 family--but, rather, Nvidia's new unified architecture. Instead of dedicated pixel shaders and dedicated vertex shaders, the GeForce 8800 cards feature what Nvidia calls stream processors, which can be dynamically allocated to vertex, pixel, geometry, or physics calculations. The result is a more efficient use of the GPU's resources and fewer processing pipelines sitting idle. The 8800 GTS features 96 stream processors, each clocked at 1.20GHz, to the GTX's total of 128. The GTS card also features a slightly slower core clock and less video RAM, among other differences outlined in the spec chart below.
|GeForce 8800 GTX||GeForce 8800 GTS|
|Transistors||681 million||681 million|
|Memory speed (data rate)||900MHz (1.8GHz)||800MHz (1.6GHz)|
To its advantage, the 8800 GTS card requires less power than the GTX. Nvidia recommends at least a 450-watt power supply for a single GTX card and 400 watts for the GTS. Another potentially big difference between the two cards, depending on your current power supply: The GTS requires only a single connection to your power supply; the GTX needs two. Lastly, the GTS is also shorter than the rather lengthy GTX.
Now, let's talk about the performance. The GeForce 8800 GTS turned in a strong showing. On 3DMark, the 8800 GTS trailed the GTX card by 19 percent and finished between our SLI and CrossFire configurations and the single-card Radeon X1950 XTX and GeForce 7900 GTX setups--a somewhat predictable and not earth-shattering result. Most impressively, however, it finished ahead of dual-card Nvidia SLI and ATI CrossFire configurations on Need for Speed: Carbon, The Elder Scrolls IV: Oblivion, and Company of Heroes. The Radeon X1950 XT in CrossFire mode topped the 8800 GTS on Half-Life 2, Quake 4, and F.E.A.R. That a single card that costs less than half of two Radeon X1950 XT cards was able to post faster frame rates on three of our six games tests--on current-generation games--speaks to the raw power of the card, to say nothing of its advanced features, which will really kick in with DirectX 10 next year.
The power of the GeForce 8800 platform is also evident at high resolutions with antialiasing and check anisotropic filtering enabled. Take, for example, the Half-Life 2: Episode One test, which is run at a resolution of 2,048x1,536. Like the 8800 GTX, the GTS card showed very little drop off when AA was increased to 16X, while the frame rates for the SLI and CrossFire configurations were cut in half or more.
Once again, thanks to GameSpot for testing the cards and providing us with the results. For more, please see GameSpot's GeForce 8800 coverage.