I was going off on a memcached tangent yesterday and discovered the mini-itx motherboard format. It's much smaller than the standard motherboard format, and most boards in the mini-itx format that I've found actually support non-intel/non-amd processors, and even come with those processors included for absurdly low costs.
So what could you use an 800mhz sub-standard processor for? There are a lot of uses actually - you probably don't want to run your windows pc on such a platform (if it were even possible, which I don't know that it is), but you could run a custom mobile MP3/GPS solution in your car, or maybe you want to build a full size Bender that says "Bite my shiny metal ass".
My idea was a little bit different. I've been turned on to the power that memcached can provide, and I thought that maybe it would be a good idea to put a couple of these in the server closet so they could sit around as memory caching servers.
The idea is viable. I priced out a 1u case with 2 1ghz mini-itx boards, 2 40gb drives, 4 gigs of ram (2gigs/server) for $1532 - with nearly $1000.00 of that cost coming from the memory itself - which is a 168 pin PC100 DIMM - and I'm sure I could get those for much cheaper on ebay or by poking my head around locally. Or maybe I could just take the 4 gigs of my slow RAM out of my own PC when I get around to upgrading it.
Even with the cost of RAM, $1500 for 3+gigs of RAM cache is a bargain, especially considering that I wouldn't have to do anything else with the machines or use any existing resources to do it.
I won't do it right away - not until I actually have a requirement for a separate database server, but if I spend any money at all on a dedicated database server, a memcached appliance is definitely in the mix.
I do question the speed of access on a slow machine like that, but all we're talking about is memory access calls and slim network transport. You certainly don't need a top of the line PC for something like that.
Heck, you could put 20 servers together on an unmetered 10mb connection and have yourself a pretty decent global search engine for a $45,000.00 investment including bandwidth.
Maybe I'll just do that and prove to the world once and for all that 90% of the value in Google and Yahoo is in 4% of their intellectual property and not in their infrastructure.
Mini-itx Commentary
