A 6360/6400 board won't work correctly, no 3.3V rail on the 5260 PSU. The 6500/5500 board makes its own 3.3V power for the PCI Slot, so those should work fine.
Sonnetize the x500 MoBo and the G3/L2 Cache will make the 5260 a whole new experience.
Sonnetize the x500 MoBo and the G3/L2 Cache will make the 5260 a whole new experience.