In bios I had the option of 'cpu,pcie sync' or 'cpu,pcie async', I went with the first.
Then 'pci frequency' options were 'sync with cpu' or 33.33mhz up to 37.50mhz, I chose the default setting of 33.33mhz. Are these settings ok?
I manually set it to 266, which worked a treat! I'm a bit...