I'm planning on buying 3-4 Ati 6950's cards for mining:

1) The card requires A 500 watts..does that mean i need a 2000 Watts PSU? What am i missing here? How many watts are really needed to run 4 of these cards

2) Also requires two 75W 6-pin PCI Express® power connectors.... does that mean that i need a PSU that has eight 6-pin PCI express power connectors?? Most PSU come with 1 6-pin PCI express...How do I hook up the other 3 videocards then?

3)What motherboard will allow me to just throw the cards in there and get them up and running without having to use risers/extenders/etc?

4)is it better to put this all in a case or have an open air solution(if so, how exactly do i keep these cards cool...no fans need to be added?)

Sorry for all the newbie questions. i am trying my very best to setup a ring and its my first time.