I'm running a 4:5 ratio. my ram is running at 910mhz. If I were to overclock more I would have to change the FSB:RAM ratio again. Here's my ram:
Newegg.com - OCZ Platinum Revision 2 2GB (2 x 1GB) 240-Pin DDR2 SDRAM DDR2 800 (PC2 6400) Dual Channel Kit Desktop Memory - Desktop Memory
I still have it set to the 4-4-4-15 timings @ the rated 2.1v.
I'm not sure if overclocking any more would be a good idea. I'm at 50C load right now at a 78C ambient room temperature. Of course, I would like to overclock more if possible. I heard that changing the FSB:RAM ratio to a higher divider would put more stress on the ram.
(362x9.5) = 3.4ghz
I have the option to set a different divider that would get me at the same ram mhz running speed at an overclock of 3.6ghz.