Voodoo5 5500 on pci-express (with pcitopcie adaptor ) :
(http://img828.imageshack.us/img828/5605/20110512005.jpg)
Voodoo5 5500 on pci-x :
(http://img864.imageshack.us/img864/341/20110512003.jpg)
Voodoo 5 5500 MAC on PCI-X,
3dmark2001se : 4697 points ( o/c 189 Mhz )
(http://img819.imageshack.us/img819/7161/30xp189pcix.jpg)
Voodoo 5 on pci-x is more faster than Voodoo 5 on pci-express.
4697 vs 3620 marks.
The best solution is to have a pcix on motherboard like Supermicro or Asus.