i found something strange here
as you know in pifast CPU frequency is really important, 2 or 3 MHZ can make the difference.
BIOS doesn't give us the opportunity to set decimal BCLK, none of the motherboard now on the market leave you set 191.3 MHZ of BCLK from bios, you can set 191 or 192 (that maybe in some cases is 191.5 and 192.5 real).
the only method to set decimal BCLK is boot at certain frequency and then adjust it with setfsb.
i've done 2 screenshot with the time of 20.95, the first one booting at 191 MHZ of BCLK from bios, the second one booting at 190 MHZ.
before run pifast i opened setfsb and adjusted the BCLK to 190.5 MHZ (as you can see in CPUZ).
till this point all is ok, the strange thing is that CPU-tweaker (even if i opened it after i changed BCLK with setfsb) continue to show the BCLK used for the boot.
there is no way to make it recognise correctly.
i hope that at least one of those screenshots is valid