I can tell you what. Many AMD 5x86 can do 160MHz. That's a common knowledge. Maybe 1 out of 20 can do 180MHz (3x60). Only 1 out of 100 can do 200MHz with air cooling and a voltage increase. Must have a lot of luck.
Today I had time to play with my new PCChips M912 and the best 5x86 I've found. This is the best among, I don't know, few dozens and I knew that it seemed stable at 160MHz and stock voltage even in a board with bulging caps (which I repaired since then).
It seems that it can take 180MHz at 4V. It boots at 3.3V too but if I exercise it for a while it finally hangs, especially with Blood. There are no other voltage options on this board save for 5V which I'd rather not try for long enough to run benchmarks.
At 200MHz it won't even POST. I couldn't even find the right jumper settings, because it won't post.
At 180MHz the cache needs to be at the slowest timings and the RAM and VLB needs a wait state. At 160MHz the cache and RAM can run at full speed but the VLB wait option is still needs that extra cycle, with every VLB VGA I tried.
All in all, it's faster than 160MHz but often not by much (Doom is faster by a large margin though), and it doesn't justify running it permanently at these settings. It definitely won't end up in a build like this. Even though the CPU itself is hardly lukewarm under the nice little copper heat sink (and fan of course) that I got from a Sun server. The VRM on the board is definitely warmer, though it still doesn't burn my hand.
Shame on us, doomed from the start
May God have mercy on our dirty little hearts