Those voltages may be ok.... I wouldn't crank the fsb that high just yet. I was talking 1475mhz... . guess I should have been more clear.
When on the 780, You WILL hit a few "holes" while climbing in fsb freq. where you will have unexplained crashes and no-posts. I still have my board, but haven't clocked her in a whiiiiiiile, so it's hard for me to remember where and how big each hole was. The one I hit in the area you are now was friggin huge though. There was well over a 50mhz (fsb) gap where nothing would happen. I have it written down somewhere....
Punx talked me through it, and eventually I came out the other side and was back in business until I hit the next hole.
You just gotta jump over the hole..... it's a lot easier than working through it.
edit: DOH! ^^^ took a while to post, was recapping my work mobo and typing at the same time.