This has been a fairly fun thing to join in and do. I started off by giving my old 2nd gen i7 Falcon Northwest tower something to do. Sure it's got a GTX580 and a 2600k processor, but it still wants to help
The computer itself has such a neat history that I can never justify getting rid of it. Maybe one day I can give it some newer video cards.
I then started adding more random towers I've had sitting around. There's a 1st gen i7 running in the garage that I tossed some old GTS 8800's into just to see if they could even do anything (I quickly learned NOPE), but at least the CPU can do something. At this point there's also an i5 Optiplex using CPU, an i7 Dell machine of sorts doing CPU, and my main tower with a slower 8 core Xeon and my GTX 1080 humming along. Nothing is overclocked, nothing is temperature monitored. Just letting things roll along and do their thing. I could probably keep adding more CPUs to the mix over the weekend here if I get too bored