ok - if no one else is willing to take a crack at this, i'll try.
Firstly, overclocking memory (using FSB to RAM ratio) has been proofed in benchmarks to wield a whopping 1 - 5 % overall performance increase. In otherwords, not noticeable.
However, if you are overclocking your memory due to an increase in FSB than the process, in your case is unavoidable. Why ? Because you're using 800mhz rated RAM. If you were using 1066mhz, it would be a different story.
If you set your FSB:RAM ratio to a 1:1 and increase the FSB over 400, you are now overclocking the RAM.
400mhz x 2 = (DDR2 is double pumped) 800mhz (which is what your RAM is rated for) Set your FSB to anything over 400mhz, ie: 425mhz you are now doing 425mhz x 2 = 850mhz. 50 Mhz more than the RAM is rated for, thus, overclocking it.
So, those are the principles of overclocking RAM and these were just examples - dont just go set your FSB to 425mhz and set a 1:1.
Apply what it is I've said above to your current setup, if needed, but I highly doubt you need to overclock your RAM anyway...