I got a bad rev 3.1 and it wouldn't do a single MHz above 100. I thought that was extremely strange. After about 3 months of trying this and that, I decided to just send it back. I'm fairly certain I got a bad board.
When I was using my Athlon 1.2, which was unlocked, I was able to run the FSB at 166 without any problems at all. But I had to run at CAS 2.5, everything else on aggressive settings. Both my IDE drive and SCSI drives didn't have any problems as well as all my PCI cards (firwire card, SB Live!, Intel NIC, and Adaptec SCSI 2). I'm currently running 150 because my locked 1700+ maxes out at 1650 Mhz.
I've been able to run 166 on it completely stable but didn't see much of an improvement compared with 133. Went back to 133 as i don't want to fry any cards or the like. Kinda a personal paranioa because back in the celeron days i fried a vid card running 83fsb.
i had my rig running at 166 stable for quite some time, nice memory scores at that speed. when i get back up and running with that box i'll post some sandra's... i was using one stick corsair pc 2100... had to get new hdd to be able to do this, before anything above 154 gave me corrupted files on the hdd.
Mine fell to 144 more or less and I had fits trying to find the reason. Turns out that if I disable the floppy drive search at startup and make the hard drive the first boot drive and the floppy the second then the system boots up to about 154 and runs stable at 150 on the fastest ram timings with crucial 2100. Floppy works fine after startup but the search for it during bootup throughs the system out. This also cured my startup problems from a cold boot. she boots right up cold at 150 fastest timings.
I was maxxed out at 145 till I tried the Doctor's vcore mod last nite. I hit 150 right away, haven't gone higher yet, still monitoring temps and stability. If you want to o/c this board, the mod makes a big difference.