Unlike on the GeForce 7800 GTX, though, the G70 graphics processor on the 7800 GS isn't operating at full capacity. In its wisdom, NVIDIA has seen fit to disable vast portions of that big GPU you see pictured above. They've chopped down the G70's 24 pixel shaders by two "quads," so that 16 pixel shaders remain. Two of the GPU's eight vertex shaders have been lobotomized, leaving a total of six. And they've nixed half of the ROPs responsible for pixel output, so that the 7800 GS has only eight.

Turns out the GeForce 7800 GS OC isn't unequivocally the fastest AGP card around. It split the difference with the Radeon X800 XT Platinum Edition-and by proxy the X850 XT that runs at the same clock speeds-in our tests. The 7800 GS is probably the better choice overall because of its support for Shader Model 3.0 and 16-bit floating-point blending and filtering. These capabilities will no doubt make the 7800 GS more future-proof, as contradictory as that may sound for an AGP card. The 7800 GS OC also looks to be cheaper than the Radeon X850 XT, if street prices work out as NVIDIA has suggested they will. That pretty much makes the 7800 GS king of the AGP upgrade market-but if you cast off your Radeon X850 XT in favor of one of these, you need your head examined. The X850 XT may lack a few bullet-point features, but it's clearly the same class of graphics card.

The value comparison between the 7800 GS and some of NVIDIA's own current offerings is less flattering. At about $200, the GeForce 6800 GS boasts the same basic feature set as the 7800 GS without that much of a performance penalty. I'm not sure I'd pony up the extra $100-150 for a 7800 GS unless I were really serious about hanging on to my AGP system for quite a bit longer. And hanging on to that system starts to look foolhardy when you consider the PCI Express-based graphics options, such as the GeForce 7800 GT, a superior performer than the 7800 GS that's selling for about $300 at various online shops. That's the low end of the projected price range for the 7800 GS. The grass is indeed greener in PCI Express pastures. NVIDIA says it has no plans to produce a GeForce 7800 GS for PCI Express, and we can see the logic if the pricing looks like this.

We didn't have much success overclocking our sample, but we're sure that others will fare better with retail products. It's also impossible to say that BFG Tech's GeForce 7800 GS OC is a generally poor overclocker based on the results from one card. It's quite possible that you would be able to reach the heights of 490/1400MHz with one of BFG Tech's 7800 GS OC video cards, so you have to ask yourself whether you're prepared to pay an extra £60 for an 18% core speed improvement.