Overclock gigabyte ga-g41m-es2h Q8200 4g ram 800mhz

THat's because you are overclocking the RAM, and that is probably limiting your overclock.

First comment: the Q8200 family is known to be not particularly good overclockesrs.

Second: Go into the BIOS and change the Memory Clock Multiplier from AUTO to 2.00. That will run your memory clock at twice the FSB frequency. The G41m being an economy board, I doubt if you are going to be able to get the FSB up to much more than 400 MHz.

it will not go more than 400, as i yesterday had the same problem, and reverted xms2 800 to ddr2-533mhz....sadly.....you will need to change your motherboard to something that supports that fsb, asus has cheap ones that go to 1600 via overclocking, thats factory overclock ability, so should be easy to take it to 1600 fsb modes....