Currently running 5x 280x Sapphire Dual x's (Running 62-68c), using
http://www.newegg.com/Product/Product.aspx?Item=N82E16813128602 as MB, and 2x 750w Gold Thermaltakes, 4Gb DDR3, Win 8.1
I have Gpu:1-4 at 725+ Mh/s but Gpu:0 is at ~680 Mh/s and can't overclock or undervolt without it becoming unresponsive 30 minutes later. I can overclock and undervolt the other cards just fine. I'm running 3x 16x-1x Powered Risers and 2x 16x-16x Unpowered Risers. I'm pretty sure Gpu:0 is using a 16x-16x unpowered riser in the 16x PCIe slot that runs at 4x.
Does the 16x PCIe slot on the motherboard not receive power since it's ran as a 4x? The other card that uses the 16x-16x unpowered riser is running fine, but I'm pretty sure it's using the actual 16x PCIe slot that is used for 16x.
Any help would be great, thanks.
