175/230 is what I usually play at. I have 5ns ESMT SDRAM memory. Obviously it doesn't mind overclocking much. I also have a 486 socket fan on my core but no special memory cooling.
I have had it up to 180/240, but it only lasts 5-10 minutes before I get visual artifacts or crashes. 175/230 is very stable. I did some benchmarking a while back and came to the conclusion that the point of diminishing returns is 170/220 or so. Past that I saw almost no change. I will have to try again with my new system and drivers.
I think I remember most people (back when the Ultra just came out and discussions were more popular) getting 170-175 out of their core. People with 5ns memory easily get over 200mhz memory. I think the Hercules has 5ns RAM, but I could be wrong.
BTW, with my setup I get Q3 High Quality Demo001 at 59 fps. Quaver gives me 46fps, and still 42fps with 4/4 texture quality. I'm running Creative Fastrac 6.34. Older 3.xx drivers would kill Quaver due to AGP texture swapping. It seems Det3 minimizes the hit. I like to play with the texture quality maxed out.
BP6, P3-700@770 (for now), 320mb, Creative TNT2U@175/220
BP6, P3-700@770 (for now), 320mb, eVGA MX Plus (dual CRT), waiting for VIVO module