what is the most energy efficent gpu out there

[Rofer]

keep in mind im not talking about lowest electricity use i mean which one gives you the highest hash rate/watt.
discuss

[P4man]

5970 probably, particularly if you use 3 of them on one board.

[likuidxd]

Depends on how many you can run on one board. I'm running 8 5870's on one board generating 1550 Watts @ 3.2GHs, that's 2.06 H/Watts.

[Rofer]

Depends on how many you can run on one board. I'm running 8 5870's on one board generating 1550 Watts @ 3.2GHs, that's 2.06 H/Watts.

how did you get a board with 8 x16 PCIe slots?

[likuidxd]

Depends on how many you can run on one board. I'm running 8 5870's on one board generating 1550 Watts @ 3.2GHs, that's 2.06 H/Watts.

how did you get a board with 8 x16 PCIe slots?

MSI Big Bang Marshal B3

https://i.imgur.com/tVUKx.jpg

https://bitcointalk.org/index.php?topic=49318.0

http://www.newegg.com/Product/Product.aspx?Item=N82E16813130595&Tpk=big%20bang%20marshal

[P4man]

how did you get a board with 8 x16 PCIe slots?

You dont even need that. PCI-E 1x is enough, all you need is a cable to convert from the 1x slot on the motherboard to the physical 16x connector of the card. It will only work at 1x speeds obviously, but PCI-E lane width is not an issue for bitcoin mining.

[likuidxd]

You are correct, one of my cards is actually on a 1x - 16x. This board has the most slots outright that I have seen though.