Athlon XP 1600+
4200ti 128mb
768MB RAM

Mild overclock.

Every setting on high or highest at 1024x768x32 with Large Unit sizes.

No lag yet. Largest battle so far has been with about 400 on each side. I'm expecting it to start getting laggy when I start fighting larger battles. The demo ran ok - but I couldn't put the settings that high - the full version is a lot smoother.