Hmmm....right now I use an X6800 with Bad Axe 1 and don't really overclock it much - just 15% on the burn and 1 notch up on the multiplier...so around 3.67ghz and it is Orthos stable. Memory is set to 800mhz but is really running 15% faster at 460mhz at 4,4,4,12, 2.2v. For higher FSB's I am sure I would need the Bad Axe volt mod for the memory as am limited to 2.2v on my ram. I believe for it to run close to DDR500 speeds (assuming I could take the fsb high enough) I would need 2.35v (according to Anands recent article on mid rang Gskill HZ 6400).
Anyway, if I had a Quad Core cpu - would it be multplier unlocked upwards. And what are the chances of hitting 3.5ghz+ on my current motherboard do you think ? If it was multiplier unlocked I could leave my memory at 800, 1.9v and just up the multiplier I guess.