is there any single PSU that can do 4x 5970's for a dedicated rig.
Yes. You need a PSU w/ at least 1200W and 4x6 pin & 4x8 pin connectors. Personally I would look at a 1250W or 1350W model.
My 3x5970 optimizes (minimalist) rigs run 870W AC. So 4x 5970 should be ~1130W AC. At 88% efficiency that 995W DC. You will want a quality brand like Seasonic and 80-Plus Gold PSU but it can be done.
would this do honestly? or would that be pushing it to close?
I have that exact supply and bought it for the sole purpose of someday upgrading my 3x5970 to 4x5970. So yes I would and likely will do it. Now a couple caveats.
1) This PSU rocks because it has a single massive 12V rail, and one of the best suppliers (Seasonic) in the biz. I wouldn't try it a Rosewill 5 rail POS. Even better it is on sale right now so ~$225 for that unit is a downright steal. Lots shittier PSU sell for more.
2) You need the system load to be as low as possible (i.e. turn off everything in bios, sempron single core, usb stick, linux, etc).
3) The PSU will be running at ~80% load. Now I KNOW that modern PSU can handle a load like that but some people swear by the keep it at 50% load. If the idea of the PSU running at 80%+ load 24/7/365 scares you then you likely shouldn't.
thank you much
I had planned to run this as a bamt headless miner with absolutely everything turned off any way.. and so far im looking at a single core sempron, 1 usb sitck, 1 ethernet port, and that's it on the mobo.
honestly i don't see any problem with loading the PSU up.. but i might buy 2, and do a test to see what the difference is on the load to the wall running with a single or a dual just to test this idea out.
ever had to warranty a seasonic?