I am using 790X-UD4P (DDR2 version) with 1090T and Bios F10a. Observed couple of issues:

1. Vcore defaults to 1.28v correctly if I don't touch the multplier.
2. Upon overclocking (multi at 20) - default vcore is at 1.44v
3. CNQ/Turbo cannot be turned off - Chip downclocks to 800Mhz on no load regardless of settings in the bios.

Overall OK - runs and overclocks fine. Still some issues that needs to get ironed out. So much for support telling me "board under validation will release bios in couple of weeks". Wonder what kind of validation they do, took me 10 minutes to find these issues