Extreme4 x16/x0/x4 Not Supported?

aR3alCoo1Kat wrote: I have a GTX 770 in the PCIE2 slot and a Intel SSD 750 in the PCIE6 slot. Hwoever, I get resource issues and the HDD doesn't always show. I moved the SSD to  the PCIE4 slot and it works fine now, but my GPU runs at x8 instead of x16. Could a future BIOS update could make x16/x0/x4 possible?

Sorry but saying your board is an Extreme4 narrows it down to about ten boards, so we have no idea which board you have.

If you have any Intel board except an X99, you only have 16 PCIe 3.0 lanes to work with.

If you have an X99 Extreme4 board, there is no PCIE6 slot on that board.

So... ??

aR3alCoo1Kat wrote: ASRock Z170 Extreme4 http://www.newegg.com/Product/Product.aspx?Item=N82E16813157633

Ok, Z170 Extreme4.

ALL Skylake processors provide 16 PCIe 3.0 lanes for the PCIe 3.0 slots. The Z170 chipset does not supply any PCIe 3.0 or 2.0 lanes to the PCIe slots.

Your board has three PCIe x16 physical slots. Their electrical connections are not all x16.

The PCIE2 slot is x16 electrical.

The PCIE4 slot is x8 electrical.

The PCIE6 slot is x4 electrical.

Since all Z170 boards and Skylake CPUs have 16 PCIe 3.0 lanes, you can only have x16 electrical to a video card if the card is in slot PCIE2, and nothing else is used in the other PCIE slots.

The best you can do is X8 electrical in the PCIE2 or PCIE4 slot, and x4 electrical in the PCIE6 slot.

A UEFI/BIOS update cannot change any of this, sorry to say.

Since the Z170 platform only provides 16 PCIe 3.0 lanes, making all the PCIE slots x16 electrical does not make much sense. Adding any other PCIe device with a video card will have the video card at x8 in the PCIE2 or PCIE4 slots.