i ran it on nc8000 with 1.6Mhz cpu, 64MB radeon, 512MB RAM, 40GB hdd@5400rmp, XP pro SP1.. standard HP drivers.. . vid card is (over-)clocked at 364/216Mhz...
i finished the demo at 1400x1050 resolution wiht all the details set to low.. the game still looked amazing.. was mostly getting around 40-45fps, but in some areas slowed down to 25-30... tried running it at a lower res and with more detail, but found higher res more satisfying..
this is a good sign in some sense, because this all means that hl2 will be very playable...
i should note that this game is really impressive!...