What's the minimum PC specification to play C&C Generals on, with all the graphics options turned on/up?

Currently I have an AMD XP2000+, 256Mb of DDR-RAM, a GeForce2 (32Mb), and a (noisey) 4 year old 30Gb HDD. And with all the options turned down, it still runs bad when many things happen at one (joint nuke/scud attack for example)

I can't really upgrade my CPU (without getting a new mb/case), so what differences can I make to get the lowest-high spec PC to run this game?