Vertex Shader Performance

When working with “pure?geometry, the GeForce 8800 GTX is for some unclear reason slower than the last-generation solutions with their dedicated vertex processors, but the unified architecture shows its best as soon as there appear light sources in the scene. The GeForce 8800 GTX never slows down much here even when it has to process as many as eight light sources.

So, this is a striking example of the superiority of a unified architecture over an architecture with independent blocks of pixel and vertex processors: 128 stream processors show an exceptional speed against 8 special-purpose ones (even though containing several ALUs in each).

When it comes to rendering several highly polygonal models in a scene with one light source, The GeForce 8800 GTX behaves exactly as it did in mark without any light sources, being a little slower than the Radeon X1950 XTX.

It’s different in the test that renders vegetation in which every blade of grass is rendered independently with the help of a vertex shader. This scene is closer to real game scenes than the previous one and the GeForce 8800 GTX feels at ease here, speeding up suddenly. It enjoys a 65% advantage over the GeForce 7900 GTX.

The analogous test from 3DMark06 produces different results. It’s Radeon X1950 XTX that is an outsider here since its vertex processors work at a lower frequency in comparison with the GeForce 7900 GTX: 650MHz against 700MHz. The GeForce 8800 GTX shows almost the same result as the ex-flagship of Nvidia’s single-chip graphics cards.

The results of the Complex Vertex Shader test coincide with the numbers from the same-name 3DMark05 test with an up to 0.1-0.2 precision.