http://hwbot.org/forum/showthread.php?t=15952

Seems to fix the multiplier wall for people of 44-48x or so random, leaving you to OC to the chip's limit.

Boards with updated BIOS in the link:

GIGABYTE

- P67A-UD4 (F6x)
- P67A-UD5 (F5x)
- P67A-UD7 (F6x)


ASUS

- P8P67 Deluxe (1053)
- P8P67 Pro (1053)
- Maximus IV Extreme (0653)

INTEL

- DP67BG (1780)