I'm into finding flexible DOS/Win31 rig these days.
After I acquired SIS530 board - Asus p5-99VM - I have always wondered how SIS530 will perform with dedicated ram chips when VRAM traffic wont hinder main RAM bandwidth. It's cost saving measure so I assume not many where made. However one popped up on ebay while little bit over my desired price range but it is rare. So I got one with what appears to be 7ns VRAM chips.

To my surprise based on Phils test suite with K6-2+ at 500Mhz difference is minimal within measuring error margin. Only clear difference can be observed with speedsys memory speeds (screenshots below)
It is however different story with fsb 66 speed, multiplier set to 2 (133Mhz) and L1 L2 L3 caches disabled.

Dedicated VRAM clearly helps (Shared VRAM vs dedicated VRAM):
3dbench 1.0 .......... 6.3 vs 7.3
Doom (slow) .......... 10 vs 11 fps
Topbench ............. 32 vs 55
speedsys mem bandwidth 36 vs 49 MB/s

It could be different story in Win9x where higher resolutions and 3D data will stress main memory more. Maybe later I run some test there as well.
However for my use case - DOS only box - cheaper MB is better.