When a bios does not support a new CPU, it locks the CPU to a safe multiplier which is 6. As long as your computer boots up without any problems, you can use ThrottleStop to force your CPU to run at its proper speed. You need to enabled EIST / SpeedStep, set the VID and Multiplier values as high as they can go, and the click on the Turn On button in Throttlestop.
If you don't know how to use ThrottleStop, send an email to the guy that wrote the program. It's in the About... box of ThrottleStop. If you can boot up, there's no need to buy a new board.