Is what I would say if my install of Valves Portal didn't crash so often. I managed to get up to level 13 without crashing, but it took me about an hour to get through the first level (as it kept crashing my whole computer). Now every time I boot into level 13 I'm pretty much instantly booted back out in the form of a full system crash.
I'm not a gamer by any stretch of the imagination, so my machine ain't the most powerful, but it should handle this. I think I may need to splash out on some more RAM for my desktop computer (which is really my wifes machine).
So, theoretically, and from my brief experience - Portal rocks.