I can "run" ultra soft shaders at like 1 FPS with my Geforce 210 (you may laugh/cringe now) if the brickcount is very low, otherwise, it can't take over a few hundred bricks or so before the driver or something crashes.
If anyone really wants to know, I'm using a Pentium 4 3.4 ghz processor (technically only one core but runs on 2 threads) with 2 gigs of ram.