I think the OP question meant 'fastest hash rate with ONE machine' - not total hash rate from some chap at a university looking after a big scientific computing cluster and mining on the downtime
One machine can have lots of graphics cards of course, but I'd like to see what's feasible with ONE logic board, I love creative solutions and seeing some mad system with loads of PSUs, one logic board, and a bunch of graphics cards independently connected to PCIe slots with extender cables, all cooled with some mad system - ideally mounted on a big plank of wood
- would be great.
Sometimes the cheaper creative solutions can outdo an expensive PC with a couple of the current top-dog dual-GPU gamer cards, after all. For my business I use top-end Mac kit which is expensive, but for mining I'm having fun building random collections of bits nailed to planks of wood. Lots of PSUs and overclocked 5850 cards seems the way to go so far