So I've been looking through my repository of parts and realised that I've nearly got enough parts to build an entire new system. I'm also away to university this autumn for my final year of study, and a final year of free unlimited internet access and free electricity.
Do you think it'll be worth my while to spend a little to put together a small AM2 BOINC-ing station using some cheap parts (probably sourced from the marketplace here).
So you need a CPU then? I'd have to recommend an Athlon 64 x2 if you can track one down, higher clock speed the better. Don't go nuts on the RAM, no more that 2Gb needed really, but you want it fast/low latency.
I've got a Sempron 64 3200+ that I picked up cheap to update the BIOS on an AM2+ motherboard. Was going to grab 2GB (probably 2x1GB) DDR2 and run Ubuntu from a tiny HDD. Got a friend who's been doing some upgrading lately and has a spare GPU that I'd nab, and just let it chug along.
Semprons are CRAP - their pitiful cache really really hurts their performance. Keep checking eBay for an Athlon x2 of some kind (even lower clock speed would outpace the Sempron).
Cheap GPU is good if you can get a CUDA/Stream compatible one