Interesting thread! I have been doing some benchmarking of my own system recently and your results are are useful comparison.
My specs in signature below. Onboard L2 disabled so I can max out the onboard RAM. In nearly all my tests, I get a speed boost from disabling onboard L2, even when I only have 64MB Ram (max cacheable on i430TX)
I have to thank Jan Steunebrink for Modding the BIOS on this board for me. I was able to get a stable and fast patched BIOS to support this CPU using BIOS patcher, but having it analyzed and tweaked by a professional is a real honour.
My voodoo3 2000 PCI is an SD RAM model
Running at 400MHz (66x6)
3dmark99 (800x600) 2843 3dmarks
Running at 450MHz (75x6)
3dmark99 (800x600) 3215 3dmarks
Running at 458MHz (83.3x5.5) -> my CPU can't do 500MHz at a sensible voltage 🙁
3dmark99 (800x600) 3413 3dmarks
My speedsys scores are similar for the CPU to yours, but the memory ones are interesting
RAM clocks (tighest timings available in BIOS)
66MHz: 135.38MB/s
75MHz: 152.43MB/s
83.3MHz: 169.25MB/s
100MHz: 203.78MB/s *I can get into DOS at 100MHz, but the IDE controller starts misbehaving and I can't get into windows
Conclusion: Unless you want to push SS7 further (550-600MHz) As long as you have a K6-3 you can moreorless skip Super socket 7 (and AGP) and keep the less temperamental socket 7 Intel chipsets
System 1: K6-3 400, MS-5158 (430TX), 256MB SDRAM, Voodoo3 2000 PCI, AWE64 (Dos/95-early 98)
System 2: Athlon XP 2000+, SL-75KAV (KT133A), 512MB SDRAM, FX5900XT, Audigy 2 ZS (late 98)
System 3: i7-2600k, P8P67-M, 2x4GB DDR3-1866, GTX 460 (XP)