Cyrix 6x86L-PR200+GP

The 6x86 PR200 processor introduced non-standard bus speeds up to 75 MHz - many motherboards and PCI cards did not support this speeds: Since the PCI bus runs at half of the mainboard bus speed, you are increasing the PCI bus to 37.5 MHz with a bus speed of 75 MHz. Several PCI cards, especially some graphics cards, did not run correctly with this overclocked bus.