The RAM you have is DDR400 - which means it runs at 200mhz, but 400mhz effective. The divider for the RAM you wanna use needs to make the RAM as close to 200mhz as possible - use a calculator and a pen and some paper to work out which you need. I'd say try running the RAM with the divider at 180, but there is no such thing as a RAM divider at 180, at least not on my motherboard.
You've got good RAM, so give 230mhz a shot - my value stuff will run at 218mhz without crashing. You may need to put some extra volts through your RAM (0.05V - 0.1V should do it) and through your CPU (0.25V- 0.5V should do it)