I have a few systems running the BOINC software: winxp64 pro, winxp, Mac10.5.5. and any other person's computer that I fix for them.

One of my work mates has just bought a new PC Linux system just to number crunch for SETI: est 500euro.,

My question is there a cheaper method of building a Good system for crunching,

I'm aware that SLI graphic cards can be paired to do this and as much ram as possible is good.. I'm looking for a CHEAP method to fill a few case's I have lying around. I want to put together a small system with a wifi card, double laptop batery's to power it and a Solar panel/wind vane to keep them toped up.. a build and forget system to see how it works out..

Has anyone built a Cheap system that they are willing to share the spec with.