Nvidia G71 – One Step Better than G70

We talked about the ways to improve a graphics processor performance in our review of the Radeon X1900 architecture. Here are the main points for you, in brief.

So, one way is to increase the number of computational units that are responsible for pixel shader execution, the so-called pixel shader processors, sacrificing other subunits of the GPU like texture-mapping units (TMUs) or raster operators (ROPs). ATI Technologies went this way as they created their Radeon X1900 (R580). This approach looks justifiable considering the tendency for more math1ematical instructions in pixel shaders in contemporary and upcoming games, but a GPU of this design won’t do too well under high textural loads. You could see that in Radeon X1600 which was severely limited by its four TMUs in many of our tests (for details see our review called ATI RADEON X1600 XT: Mainstream Performance Redefined Once Again?). In the same manner, the new Radeon X1900 XTX was not any better than the older Radeon X1800 XT in certain tests because the two cards had the same number of TMUs and ROPs.

The way chosen by Nvidia implies that math1ematical computations and texture operations have the same share in games. A GPU created according to this principle has about the same number of pixel processors and TMUs. For example, the GeForce 7800 had 24 pixel processors, 24 TMUs and 16 ROPs and it felt at ease in textures-heavy applications. The new graphics processor from Nvidia carries this principle on, but some expectations concerning the G71 haven’t really come true. The G71 was expected to come out with 32 pixel processors, 32 TMUs and 16 ROPs, but Nvidia must have thought it proper not to redesign the G70 that dramatically, and the G71 differs from it but very little:

The table tells you the technical characteristics of the senior model of the new GeForce family, but the less powerful GeForce 7900 GT just has different clock rates, 450/660 (1320) MHz and is equipped with half the amount of graphics memory (256MB).