What do you mean per slot? Per port yes, but you can get dual ported HBAs which will double that, so 2 dual ported cards give you 2GB/s. And that is if you stay on fibre. What about infini-band that is 10 or 20 Gb/s isn't it?

Well I've never poked around the price of these things but if you need 4TB of storage at that level I would expect the hoops you would have to go through to get enough fusion IO cards in single system would probably make it fairly cost effective and certianly simpler and easier to maintain.

I guess you also get into the traditional arguments of SAN vs DAS storage efficiencies and sharability etc.

I'd still like one for christmas 🙂