6 R9 280X PSUs

[NameTaken]

My 280Xs that I ordered 3 weeks ago finally got in stock today so I'm going to be expanding my rig to 6 R9 280Xs. I'm wondering if there are better PSU options than 2 of these (in Canada)?

Also, I have an AMD Phenom II CPU and motherboard so I'm wondering do PCI to PCI-E adapters work?

[CMD7790]

Do you plan on running multiple PSUs or just one big one?

How many PCI-e slots do you have on the board?

Risers are fine and you can spread the cards out so they run cooler.
Make sure to get powered ones so you don't blow out the board.

[NameTaken]

Do you plan on running multiple PSUs or just one big one?

How many PCI-e slots do you have on the board?

Risers are fine and you can spread the cards out so they run cooler.
Make sure to get powered ones so you don't blow out the board.

Likely 2 unless there is a really good incentive for a single PSU which what I'm asking. H81 Pro motherboard have 6 PCI-E slots with dual supplementary Molex adapters so powered risers aren't needed. The cards will be suspended 3.5 inches apart.

[CMD7790]

There is no advantage to run one big PSU with that many cards.

Those PSUs should be fine to run the cards.
They would be near the limit though the cards pull around 17A-22A each depending on the OC.

You might need 1 more small one to run the board/cpu/hdd etc and power the extra Molex adapters.

[NameTaken]

There is no advantage to run one big PSU with that many cards.

Those PSUs should be fine to run the cards.
They would be near the limit though the cards pull around 17A-22A each depending on the OC.

You might need 1 more small one to run the board/cpu/hdd etc and power the extra Molex adapters.

With the first PSU powering the 24 pin ATX and second PSU powering the CPU and Molex, I would think 1700W of combined power to be enough? All the cards will be undervolted.

[CMD7790]

It is enough power to run. 

I personally don't like to load a PSU more than 85%.

[NameTaken]

It is enough power to run.  

I personally don't like to load a PSU more than 85%.

The XFX Pro Black Edition is a rebranded SeaSonic KM3 so I would not expect it to fail anytime in the next few years even at 95%+ constant load. But I'm wondering if there are better PSU configuration setups?

[brooklynite]

Are you guys saying 2 x 850W PSUs can run 6 x 280x GPUs plus MB+CPU+HDD? I am in the same boat but dont have my cards yet.

[CMD7790]

With a 6 card setup you would need at least ~140A combined on the 12v rails.

I'm running a 4x rig with 2 Antec 650W to power the cards and 1 Corsair CX430 to run the board/cpu/risers etc.