Motherboard Voltages on Asus P5WDH

I was having some problems with my memory being unstable on memtest when i OCed it a bit to 850mhz. I upped the MCH ICH and FSB temps but wanted to know whats a safe limit to set those.. and also which ones have to do with memory? my mobo doesnt have much active cooling on it but i do have good case airflow. Also what would be better to run at 800mhz at 4-4-4-12 or 1000 at 5-5-5-15? Thanks for all the help.

I would up the voltages on your memory more than mch. I have my ddr2 800 at 1000 but the motherboard won't boot it at 1000 I have to use memset to lower the sub timings in windows and then clockgen to raise the fsb. the motherboard can handle up to about 950 mhz on ram without a raise in MCH.

Running ram at 1000 5-5-5-15 is going to be faster than running it at 800 but I would stick to a 1:1 ratio for memory:fsb

WIth the P5WDH, if you are running memory 1:1 with the fSB you will not get much past 850....