Try to overclock cpu to 83x3.5 or at least 75x3.5 and quake ii and unreal will be barely playable

well that CPU won't push either of these cards to their limit , so both are more than enough, though sure if you can get the Voodoo4 for the same price, might as well go for it just for the few extra features it has

just remember the kind of games that really benefit from the 32 bit colour and large textures of the V4 will also really strain a system like that

That system is more fit for a V1/V2 than anything else, a V3 won't see anywhere near its real potential till it is used with a P3 or higher. The v4 is even more needy and is best pared with a P3 or Athlon not a P1 MMX. 3DFX card depends on systems with fast cpus more than other cards. Start looking for a card that can properly offload more of the work from the cpu and has a lower penalty when used on old/low end systems. I suggest that you look to build another rig that can handle the games that you wish to play better than this rig. Take that cpu to 289mhz by setting the fsb to 83mhz and leave the multiplier where it is. Note running the agp and pci clocks so high can cause issues but if you work at it you shouldn't have major issues.