My K8T did that as well. It auto-detects a working divider for the memory. I guess the memory couldnt handle the cut. I ran a 5:3 divider (after taking it off auto), I suggest you do the same. However the max overclock I get is 2.5 Ghz with a 5:3 until I get BSOD's. At least the memory was at 200Mhz though.
I also used clockgen to set the over clock to figure out 2.5-2.6GHz was the max. Clockgen is a handy over clock tool to use while windows is booted up. Without it I would of been stuck on boot with the bios auto dectecting some absurd divider like the one you have set now.