I have like an 7 year old computer that only got tweaked a bit. The only thing I did for this release to work fluently:
Turned off Multisample for quality. Checked Preload Models. Increased the full screen resolution to 1280x1024 (native resolution)
And very important: inGame I turned on Adaptive Distance with (30,15,30 I think). Sometimes you see weird graphics in the distance, but it doesn't affect performance.
800 MHz Arch Linux 512 MB RAM GeForce 5200 256 MB (set the commas appropriately :-P)
PS:
Yes, I tweaked the maximum out of that motherboard, anything else would be a complete new machine..