nVidia GeForce 8800 GT Performance Scaling Analysis

[RobRich]

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The first game tests of NVIDIA GeForce 9600 GT were amazing - its results were very close to those of the more powerful GeForce 8800 GT. Of course, we expected that the new G94 would be fast and well-balanced in main parameters (the number of execution units, memory bandwidth, etc). However, in the first game tests GeForce 9600 GT almost caught up with GeForce 8800 GT, even though the latter has more TMUs and ALUs. Frequency hasn't been increased much relative to the G92-based card, and video memory bandwidth hasn't changed.

So why is the G94-based card so strong? What about almost twice as many TMUs and ALUs (there are precisely twice as much of them, if we compare GPUs, but GeForce 8800 GT has only 75% more of them) in G92? Do they make no difference in all modern games, and rendering speed is mostly limited either by fill rate (ROP frequency/number) or video memory bandwidth, or both?

Some of the advantage of G94 in the first tests can be explained with different driver versions (for old and new solutions). But the average advantage of GeForce 8800 GT over GeForce 9600 GT in equal conditions is still only 15%, which is much smaller than 75%. We decided to find out what parameters affect performance in modern games most of all. Besides, we haven't analyzed how performance is affected by CPU/GPU/video memory clock rates for a long time already. So we decided to test a G92-based graphics card and determine main render bottlenecks in modern games.

Source: Digit-Life