The Visualizer is not able to get much out of high processor speeds. The real differences result from the use of those three graphics boards. The GeForce 2 Ultra is definitely a better investment than a Pentium III 933 plus any of the slower graphics cards.
SPECviewperf 6.1.2: Lightscape
Lightscape demands strong performance from both the CPU and the graphics card. Still a fast graphics card is more valuable than the fastest processor.