Q6600 b3 780i evga overclocking help


Apr 13, 2009
hey guys im having a real hard time trying to get this setup to 3.4ghz

its just unstable and runs hot. prime95 always shows 1 cpu failing.

here are my specs

q6600 b3 1.3125v vid

3.4ghz (1512x9) in evga 780i bios

evga 780i sli mobo

6gb corsair 800mhz 2x2gb 2x1gb 5-5-5-18 (2t)

1.360v core
1.4v fsb

everything else is auto ive tried bumping up northbridge voltage/memory changes/ basically tried bumping every setting in bios 1 by 1 nothing helps.

right now my temps are

44-48c idle
65-70c full load !!! super hot!!

i have thermaltake v1 cooler
antec 900 case
about 6 120mm (1 for exaust) antec fans
1 220m exhaust on top fan

i think i am going back to 3.2ghz it was stable then and alot cooler but
i just cant believe my system cant handle anything higher then 3.2ghz
as it seems really cool inside and the air it blows out is really cool air.

im using core temp, speed fan, cpu-z , prime95
i put tj max on core temp to 100% so i should be getting the right readings.

what do you guys think? can my system get pass the 3.2ghz or is it the best it can do?

oh and i've unmounted and mounted the cpu cooler many times and making sure the thermal paste was evenly put on there.


Apr 14, 2009
You need to increase your vcore - but you'll need to change cooling. I'd recommend the xigamtek s1283.

I had a Q6600 oc'd to 3.5 with a 1.45vcore - loads @ 68c - which is about as high as you can safely go with Air. I was using a cheaper board - a Biostar P43 (I've since sold that system).

Your idle temps are a little high, but not by much for quad standards.

3.4 - 3.6 is about the standard max for a q6600 on air... so you're not that far off. Also, consider your b3 revision may be your bottleneck as well - G0 is what most peeps are getting high OC on with the q6600.


Jun 1, 2009
Don't be surprised if you can't go above 3.2 with your B3. I have the same mobo and CPU as you and I can't seem to get above 3.0 (1.35vcore) and keep stable with the prime95 small FFT test.

I was trying to get to 3.4 not long ago and I had to bring my vcore up to somewhere around 1.525 to stay stable in the large FFT test, which brought my temps up to 62C on the diode, 71C on the cores. According to intel's spec sheets for the B3, that's their max temp; and their max VID is 1.5v. The small FFT test would fail within about a minute and would bring my temps up to 70+ on the diode.

I'm using a thermaltake ultra 120 and a 3k rpm 133cfm fan (beastly). I get ~53C accross the board under load at 3.0.

BTW optiprimox, just curious, were you running a B3 or a G0 at 3.5?