Is the motherboard a Asus Crosshair II your referring to ?
Actually its the Asus Crosshair.
you can't get a that much more powerful cpu on that board.
yea the best you can get is the 6400 which is 3.2 and 169.00 on newegg. If I where you just overclock it. you can reach 3.0 probaly. but just save your money or put it towards anoth part like a hard drive or video card for future builds
I think the board is only up to dual core CPUs.
No correct my earlier post this motherboard can even support X4 Phenoms even thought they weren't that good of a CPU.