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PCIe Lanes Explained....Please

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Jan 12, 2015
I have a GA 990FXA-UD7 with 6 PCIe slots. I can only use 4 slots for folding. The manual states that I have 32 PCIe lanes, used as x16-x16 or x8-x8-x8-x8. I also have two x4 lanes that don't work when the others are used :(
Q: Would using x1 risers help to give back PCIe lanes to the x4 slots or just be happy folding with 4 GPU'S???

Thank You For Your Time.
From here:

(Note 3) For optimum performance, if only one PCI Express graphics card is to be installed, be sure to install it in the PCIEX16_1 slot; if you are installing two PCI Express graphics cards, it is recommended that you install them in the PCIEX16_1 and PCIEX16_2 slots.

(Note 4) The PCIEX8_1 slot shares bandwidth with the PCIEX16_1 slot and the PCIEX8_2 slot with PCIEX16_2. The PCIEX16_1/PCIEX16_2 slot will operate at up to x8 mode when the PCIEX8_1/PCIEX8_2 is populated.

The way that I read it is that the PCIe 8 slots share with the PCIe 16 slots when used. The two PCIe 4 slots and the one PCIe 1 slot are separate.

With that said, folding on anything less than PCIe 8x slows down production and perhaps is not the most efficient way to use your hardware.