The standard 7800GS is a partially disabled 7800GTX, Nvidia has opted to disable 8 of the 16 ROPS, 2 Vertex Shaders have been disabled leaving 6, the 24 Pixel Shaders have been halved leaving 16 and last but not least the GPU clock has been reduced to 375MHz. 430MHz is standard for the GTX and the memory speed has been unchanged from 1.2GHz..



Link: Tech Array