Ok, folks, here's my current setup.
Abit KT7-RAID
Duron 600, stock heatsink and fan.
I was getting weird errors in Windows 2000 at 900 (1.75v), and was having problems where the machine would occasionally not post. Not all the time, mind you, but frequent enough where it was causing a little heartache.
But the oddest thing is that my USB mouse and keyboard would occasionally stop working, but the system would still respond. I know this, because I switched back to the PS/2 keyboard, and when the mouse would stop responding, the keyboard still worked.
Anyway, there is a note in the KT7-RAID manual about PCI slot 5, and that it shares resources with the HotRod100 controller. This was my SBLive in that slot, so I moved it to Slot 6. I also moved my Network card to Slot 4 from 3 ... since my freezes tended to happen when accessing the Internet.
I'm also back at 600 for right now, while I get stuff installed. I'll give another progress report later. But I would like to say that for the most part, 900MHz worked!!!