I have the same issue with my OCZ reaper DDR2 1066. It shows as 335mhz in cpuz, and it should be at least 400 right?
In my bios, I found HTT multiplier, CPU freq and Multi etc, but no CPU:RAM ratio. Could it be called something else.
I have a Biostar TF570Sli, and XP Pro SP2 32bit, 5400+ BE @ 3ghz (15x202)