This issue concerns how well a video card scales. As you see benchmarks of a certain video card varying with different processors, you can see how well the video card scales with respect to the processor.
of course back in the day, processors used to carry out the T&L operations. now, the radeon and geforce GPUs do that.
there are 2 things you can notice (fps = frames per second, max, min, average, what have you):
1. the fps acquired by the video card hits a flat spot as the processor speed increases. while for slower processor speeds, we see definite shifts in fps. this is where the video card becomes the bottleneck, usually the memory subsystem of the video card if you carefully examine the results. we critics of hardware have said this often actually. here increasing the speed of the GPU increases the fps achieved.
2. the fps acquired by the video card hits a certain flat spot as before. however changes in the speed of the GPU does not increase the fps at all. here 2 things are possible, there is just not enough memory bandwidth for the video card to do anything, or the processor is limiting. even though T&L are done by the card, the processor still has work to do.
of course there are a wide variety of hardware modifications, upgrades, that can affect the performance, such as the amount of MAIN memory you have.
You will have to read certain reviews of CPUs and video cards to gain a proper perspective on things.
The GeForce3 Ti500 is a very fast card. I do believe that the 733 is the bottleneck of the system, IF a bottle neck exists. of course how much RAM you have does affect things.