Well,
I tried setting the CPU multiplier and the FSB speed. Neither seemed to have any effect.
It was clear from other BIOS settings that I was doing the flashing right--everything else that I was setting was getting properly set into the BIOS upon reboot and floppy installation.
Is the D945GPM somehow "locked"? What's going on? I thought this was going to be my magic trick to overclock this board.