Just flashed my DQ6 from F3G to F4D (from the link provided above) and it seems to be slightly better at overclocking - perhaps another 25-50MHz - I'm still priming to see if 500Mhz FSB is stable.

Oddly, though, F9 in the BIOS shows:

F2
06/29/2006
6A79LGOG

Is it possible it's just renamed?