I didn't keep it on Auto, I set it back to 1.45v. I don't know why it went back to Auto in the first place but my guess is that when I rebooted, the Vcore voltage spiked and scared my board stiff. So it reduced the Vcore, however with the FSB set to 1600, it couldn't provide enough power to boot.
If I persisted I could probably find a good balance to get 1600 running. Like I said previously, it was running stable while the PC was on, it wasn't too hot and didn't encounter any problems with my stress tests. It was just when I rebooted that it zonked out.
It was a close call, I was "this" close to doing a CMOS reset. I'm not going to try for 1600 again. I don't think I'll even try for 1500. This last scare was enough to get me to stop. I'm done trying to push this board. For whatever reason it wouldn't even boot with 1600 unless I put 1.56v into the NB, which was a little too high than I was comfortable with.
I guess I got a wimpy board. I envy you who can get 3.2ghz from 1.375v on the Vcore and 1.39 on the NB. Mine won't even post with those settings. Perhaps in a couple months (or years) when ASUS gives us a new BIOS they were tighten up these issues, and I'll make another attempt.
Or I'll just wait until next winter when I get my Xmas bonus and just buy a Quad Core