The GeForce 7800-series was an evolutionary development of the preceding 6-series that basically increased the number of pixel and vertex processors, while also ramping up clock speeds. Like their 6-series forebears, the GeForce 7800-series cards also support SLI. Although it's pretty hard to buy a 7800-series card now, it's highly possible that one may be lurking inside your PC, so it's interesting to see how they compare with more modern graphics cards.
The 7800 GT was the mainstream 7800-series card, sporting 20 pixel processors, 20 texture processors, seven vertex pipes and 16 ROPs. The GPU is clocked at 400MHz, while the 256MB of GDDR3 RAM runs at 500MHz (1GHz effective). This wasn't enough to run Need for Speed: Carbon and S.T.A.L.K.E.R. at playable frame rates, although it was capable of delivering a smooth frame rate in F.E.A.R. at 1,680 x 1,050 with 2x AA and 8x AF, an impressive feat for such an old card.
The 7800 GTX and 7800 GTX 512 have a slightly different architecture to that of the 7800 GT. Although they have the same number of ROPs, they have 24 pixel processors, 24 texture processors and eight vertex pipes. The 7800 GTX is clocked at 430MHz, and accompanied by 256MB of GDDR3 RAM running at 600MHz (1.2GHz effective), while the 7800 GTX 512 runs at 550MHz and has 512MB of GDDR3 clocked at 850MHz (1.7GHz effective). The 7800 GTX 512 was the only 7800-series card that was capable of playing S.T.A.L.K.E.R. and Need for Speed: Carbon smoothly at 1,024 x 768, while the 7800 GTX jerked along behind.
The 7800 GT and 7800 GTX struggle to cope with modern shader-intensive games, so if you own one of these cards then you should definitely consider an upgrade, probably to a 320MB GeForce 8800 GTX. For owners of 7800 GTX 512 cards, the situation isn't nearly as bleak, although even this once mighty card can only handle modern games at low resolutions.
Author: James Gorbold and Chris Lee
NVIDIA GeForce 7800 series