memory speed & cache size
Karnivore, your results seem to stress the importance of a large L2 cache. I am impressed that you seem to be getting a +5% increase in 3dmark performance by just an increase in L2 cache size.
I was wondering: at what speeds did you run the memory? Was it always at PC2700?
If so then the CPU will be more memory-starved than in a PC3200 config and will therefore very much like the extra cache memory.
Also, the CPU bus speeds differ, but I don't know if that is such a great difference. RAM however I am not so sure. Perhaps, once you get new CPU's, it's possible to check both CPU's at both the same hypertransport bus and clock speeds?