Any computer capable of running Windows XP can be used for the server.
Please keep in mind that VIA and CIRIX chips are known to generate lots of performance problems under linux and schould only be used as a last resort.
For best results i advise the use of a 64-bit processor with 4GB RAM, SATA-3 Harddisks and Giga-bit ethernet. The number of supported hardware combinations is almost limitless and will give a broad range of performance differences. Therefor we ask our users to do some performance testing on their servers and report back on this page.