Huh?
The vanilla P6T has three PCI-E X16 slots, one PCI-E 1X slot, and two PCI slots.
The P6T Deluxe V2 has the same number, although the slots are in a different order.
(I have an older Deluxe, which includes an SAS controller, which I'll probably never use.)
I don't see any P6T variants with more PCI slots. Seaching my favorite online resource (
www.newegg.com) doesn't return any Socket 1366 boards with more than 3 PCI slots.
The P6T Deluxe has some, er, deluxe features, like 16 phase power. Whether any of these enhance the overclocking ability of the board, I have no idea. I bought the Deluxe because it semed to have better BIOS support. (That doubtlessly guaranteed that it would be taken out of production and replaced with the V2.)