The G41 chipsets are not good overclockers,they are for basic computing needs.
Gigabyte website lists memory at highest of 1333 thru overclocking(intel speedstep)
Default for the board is 1066.
the mobo should run great at stock clocks
cpu=1333
mem=1066
If you are trying to overclock to play most recent demanding games, you are better off finding a new or used P45T.
Just my 2 cents.