Using 2 seperate PSUs for 4 to 5 x 7950s

[AceCobra1]

Any ideas if I need to CONNECT 2 700w PSUs or can I just use 2 unconnected PSUs ?

For example, if I use 1 for connections to motherboard and 2 graphics card and the other PSU only utilities the connection to 3 GPUs with the rest of the connections unused?

[Ratman2050]

You can make it work, the only thing is you need to make the 2nd PSU work without being connected to the motherboard, this is not that hard to do, you can buy an adapter called add2psu or you can do it yourself:

https://bitcointalk.org/index.php?topic=14408.0