It will depend on what PCI dividers your motherboard supports. (PCI bus= FSB/PCI divider: i.e. 100/3=33, 111/3=37, 133/4=33, 150/4=37.5, 166/5=33 etc.) Some support 3, 4, and 5. My AK31 only supports 3 and 4, but I can STILL crank her up to 166 without trouble. Of course that means my stuff is running at 41MHz, which is REALLY high, but it hasn't caused me a problem. As far as it goes, you'll either have to do exhaustive research on your board to find out which dividers it supports, or just try it. And if it fails at one speed, try kicking the bus up a few more megahertz, because it might just kick in another pci divider!