new computer games

a few weeks ago I came across the place where I had installed the Supreme Commander demo but never run it...so I fired it up.

well, no I didn't. after thinking for a short while, it decided my computer isn't fast enough. huh? granted, it's not top of the line, but I have more than a few games that run quite well on it...I think it was unhappy about the clock rate.

I have an AMD 3800+ X64 dual core. I run XP x64. I have an ATI X1600 (all those X's, gotta love it). So why is that insufficient?

Today, I was at Best Buy (getting a 1GB mem upgrade stick, so now I have 1.5 GB). Also had a look at the Bioshock boxes. says it wants a 2.4 GHz Pentium...how does my cpu compare to that? what about other new games? am I going to be out of the market soon? this machine runs UT04 just fine, Oblivion and HL2 likewise.