I have a GA H55M S2H board and a Gigabyte R7 260x GPU.

The GPU is in a 16x PCIe slot but is constantly underperforming because it is used in a PCIe 2 1x mode even under full load.

I tried everything with the GPU drivers so now I suspect my problem might have something to do with the MB or the MB-GPU synergy.

BIOS version is F5.

Also, Catalyst Control Center displays this under hardware stats tab:

Under CCC Hardware info it says:

Graphics Bus Capability PCI Express 3.0

Maximum Bus Setting PCI Express 2.0 x1

Core Clock in MHz 1188 MHz

Memory Clock in MHz 1625 MHz

Total Memory Bandwidth in GByte/s 104.0 GByte/s

BIOS Version

Please help.