OK, following a slight delay in my folding plans I now have more time to think about setting up a low-power, low-budget folding rig. I'm looking (I think) at 3 basic options:
1) fiddle with existing Socket A set up.
I have an aging socket A PC that is about to be retired as my primary office PC, and I'm loathe to just let it go. Research has pointed me towards AMD Geode NX processors, which are basically very low power Athlon XPs, and I've found I can pick one up for < £30 (off that much lo(v|ath)ed auction site). I could then add a new(ish) AGP graphics card - e.g. HD4650 - and do GPU folding on that. The TDP for the Geode NX is only 25W, so even fully loaded the power draw shouldn't be too horrific.
2) mini-itx + PCI GPU
There's plenty of cheapish low power Atom / Via / Geode LX / etc mini-itx boards out there, all armed with PCIc slots. Now, I know PCI is massively limited in terms of bandwidth, but I was wondering how bad the limit was, and whether it would bottleneck a PCI graphics card (e.g. HD2400) during GPU folding.
3) new low power build
Given how taken I am with my Sempron 140, I could build a new machine based on a cheap 780V/G motherboard + Sempron 140 and fold on the IGP. I assume this would work, since the IGP is basically just a 2400 with no dedicated RAM.
Now, I think pretty obviously the first option would give me the greatest folding power, but it would also draw the most power and I really don't want my electricity bill going through the roof!
The second option appeals aggressively, mostly because I think I like the idea of being able to fold on a tiny little Pico-PSU powered box. With spare bits of kit I've already got lying aorund this shouldn't set me back any more than option 1, and while the throughput won't be nearly as good, it should draw significantly less power - in the region of half, if I'm any judge.
Option 3 would have to wait as I don't have the cash for a new build, but is probably the safest in terms of usable technology. It'd also leave me the option of getting a more powerful GFX card later (on a more sensible PCIe interface) to increase the folding speed. But where's te fun in building anothrer eneric made range PC, huh?
So, any thoughts? What would you do in my situation? (All three is not an acceptable answer, btw ). Will PCI bottleneck GPU folding (even on a measly 42GFlop 2400)? Does that matter, given the inherent coolness of a tiny itx folding machine?