SERIOUS Phenom II 940 OC Question

[magruder13]

Yo, i got a phenom II 940, i overclocked it to 3.5GHz, I moved the multiplier from 15 to 17.5 but after that it is unstable, is there anything i can change to make that more stable? I have liquid cooling and my CPU dosent even approach 40C under a load so any advise would be amazing.

Mobo: Gigabyte GA-MA770 UD3 Rev.1

 

[mindless728]

up the cpu voltage

 

[keefygeorge]

Specs,
Antec900 case, PhenomII 940x4, Cooler=Zalman CNPS9500, GA-MA790FX-UD5P board,
Only have Kingston DDR2-800 aultra slim ram at the moment.
HD4870x2,CoolerMaster real power M700 PSU 750w.

Settings.

CPU multiplier set to x18 with cpu voltage set at 1.3625v
Havn't altered the NB speed yet but im running stable with these settings.
I ran AMD OD stress test for four hours and prime95 for 3 hours with a max temp of 48 degrees.
Also post your specs.