Why all the problems getting higher multipliers, and Bus speeds? I have a DFI mobo, and my multiplier in bios goes to 30x. I am running currently a 5000BE at 3125mhz @ 12.5X multiplier, 250mhz Bus, with +0.25 gain@1.392V. Stock is 2600mhz, 13x multi, 200mhz bus, and 1.350V. Always lower your multi before raising your bus, then voltage, then raise your multi. BE cpu's can hit 1300mhz bus...but dont push it. Make sure you have a good PSU aswell.
That 7750 is supposed to hit 4.0ghz no problem, and I will be getting it soon. Don't forget it's based off the phenom core design.