Uhmmm... something "embarrasing" really considering your average video card these days would walk all over it.
Silicon Graphics Onyx2 with Infinite Reality 2 Extreme graphics and (apparently) 2x 350MHZ MIPS R12000 CPUs. It was the "deskside" workstation version weighing in at a lightweight 80KG.
Similar to this one in outward appearance:
http://storage.g-lenerz.de/images/sgistuff/onyx2/onyx2_2200_front.jpg
http://storage.g-lenerz.de/images/sgistuff/onyx2/onyx2_2200_back.jpg
There's apparently one in Holland, but spec reads 2x 195MHz MIPS R10000 processors and just Infinite Reality 2. But it has the 8 monitor display board which would have been fun.

This one has newer skins in perfect condition so I might actually go for it sometime in the future and get the boards as I find them, but the big-ass R14000 500MHz processor boards (can have 2 in the machine) cost a bloomin' fortune.
And don't compare MIPs processors to desktop processors in terms of CPU speed. The architectures are very different.
PSU is about 3KW, I think it needs 2x 230V 30A circuits so even if I didn't get it fired up I'd at least have some heat in the house during winter.
This onyx2 thing is actually the newer version of what I've been after since maybe 1994 since I first played with one, an original onyx.
And don't diss it... the engineers from Silicon Graphics are the boys that created the GeForce back in the day.

And OpenGL used to be called IrisGL. Man, SGI really got run by a bundle of twats. They filed again for chapter 11 in Feb this year.