OC with factory Voltage and fan?

So I wanna overclock my Q9400 but I dont want to fiddle around with voltages as Im new with this. I just want to know whats a good, stable and full-proof increase? Its at 2.66ghz is 3.0ghz a good speed assuming a leave the factory voltage and factory fan for my cpu?
Specs:
asus p5k-e motherboard
intel Q9400
Gigabyte gtx 560 @ 900mhz
4 gb DDR@ hyperX ram
600w cooler master

Much appreciated!

what speed is your ram? you might be able to do 3ghz without bumping up the voltage but your temps will still go up a bit. your asus board is a p35 chipset and the q9400 are both known to be great overclockers. you might need just a slight bump to get it stable. i would start small and shoot for 2.8 and take it from there, good luck!

i'm sorry but no one can tell you the exact amount of voltage because every cpu is unique and results will vary. if you must start at 3ghz i would first try it without adding any more voltage, if you get a bule screen of death go back and bump up the voltage by the smallest amout your allowed to make and repeat until your stable. dont forget because your overclocking the cpu it will also overclock your ram because it shares the same bus. i would never go over 1.59v, i think normal is 1.35v and keep a eye on your temps, hope that helps.

for what your trying to do you dont need to change the cpu ratio. you need to raise your fsb frequency and that will overclock your cpu and ram. just multiply the fsb number by the cpu ratio number and that will tell you what speed your cpu will run at. i have a Q6600 with a cpu ratio of 9 and a fsb frequency of 377 which equals 3.4ghz