X-bios have post a guide that will hopefully simplify the new hexadecimal system of setting Refresh Rates in Detonator 40.41 ! Here's a snip.
Now, to eliminate the Win2K/XP refresh rate problem we want to specify custom refresh rates with the corresponding resolutions and bit depths. In other words we only want Windows to use the HIGHEST refresh rate supported by our monitor in any given mode, not the LOWEST as it will if left to it's own devices. We do this by adding '80**' to the hexadecimal refresh rate. Refresh Rate Fix for Nvidia Detonator 40.41
Now, to eliminate the Win2K/XP refresh rate problem we want to specify custom refresh rates with the corresponding resolutions and bit depths. In other words we only want Windows to use the HIGHEST refresh rate supported by our monitor in any given mode, not the LOWEST as it will if left to it's own devices. We do this by adding '80**' to the hexadecimal refresh rate. Refresh Rate Fix for Nvidia Detonator 40.41