Just got SC2 beta loaded up on my 8 year old Dell, and surprisingly - it runs fine. With everything turned to low, the P4 2.8B Northwood, 6800NU, and 1gb of RAM can manage to pull through the game at a manageable framerate. I can't take too many zerglings on the field (so a lot of UMS is out of the question), and I lag a lot, but it's totally playable - no suffering at all. So far I'm 4-0 in my placements, all against very bad players - none of them did a proper job of scouting my base, so I went fast phoenix on all four of them, harassed their overlords, took out their queens, then macro'd up and teched to colossi, immortals, and chargelots, with a few stalkers for flavor. I really like this strat, because it forces Z to go blind without overlord sight, forces them to waste drones and resources building spore colonies, and forces them to go mass hydras, which are owned by colossi and chargelots. Then again, I wonder how this strat will work against a real zerg player...