I've lurked here for a long while and just now joined so I could answer up...
I have the same board (rev 1.0, not 3.3) and I've been running a 6300 oc'd to almost 3.2Ghz. I broke down and got an 8400 (reading on other forums that this would work). Updated bios to latest (f13i, I believe), reset to optimized defaults then dropped the chip in. Nothing. No post or beep codes, only a black screen.
I tried setting the bus speed to 333 while the 6300 was still in, then swapping chips, that didn't work either. Long story short, the problem (on mine, anyway) was that I was killing the power via the power supply (out of habit, like grounding yourself and all that)
The last time I tried (and the one that worked), I reset the bios to optimized defaults, saved, powered down. Without turning the power supply off completely I swapped chips, and it fired right up. Everything works through restarts and shutdowns, but if I kill the power to the PS it won't boot again.
Could be a problem with the rev 1.0 boards, not sure, but I tried this with 2 boards, both of which work fine with other chips (6300 and 6400).