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If he put a pair of 12" fans over the Gpus
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Just in case that confuses someone who uses double quotes to indicate inches, Juan is from Brazil and I assume he means centimeters...

                                                                   Joe

Thanks Joe, my mistake, we only use metrics units here. Yes i mean 12 cm (normaly i use spares units who comes from defective Midrange PSU´s), in the future i need to remember some places still use inches.

Something like this: http://www.newegg.com/Product/Product.aspx?Item=N82E16835103052 mounted right above the GPU´s at about 2-3 cm (1 inch) of distance to allow the air flow.

Smaller fans has few air flow capacity, so they cool less. Bigger fans could work but as the are so big few of the air is realy pass in the board itself, my tests show 12cm is the optimal one, uses less power and produce less noise.

Taking out the air in the case of the vertical mounted heatsink (EGVA ACX colling or the Gigabyte 3 fan model for example) or blowing air inside in the case of the horizontal heatsinks (like the 670/690).

My sugestion is, trying both directions and choose the one who make your GPU running cooler. Yes i´m an electronic engenhering and i know and we learn in the school take out the hot air is the best technic, but some hosts runs cooler exactly in the opositive direction, why? i have no ideia just guessings.

<edit> Some could ask why this all? You need that if you with to push your GPU´s to the limit and live in a hot place, uses no AC or could not use any other cooling (water, collants, etc) like me. Hot is the enemy of any electronic component, specialy CPUs & GPUs.

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Ok, got the wife's permission, but after doing a final check on my MB spec (link posted above), the specs of it say that it is PCI Express 2.0 compliant, whereas all of the GPU's listed are the PCI Express 3.0 interface. Other than this little nugget, I'm ready to buy. Anyone have any guidance on this issue?

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PCI-e 3.0 cards are backward compatible with 2.0 so you shouldn't have a problem.

Cheers.