asus p7h55 i5 760 4.0ghz oc help thread

I got my new computer from newegg a few months ago just for a good gaming pc because my school lap top wasn't cutting it. After some research on the i5 I found out it can run at 4.0ghz and be stable so I had to try. It's my first attempt at oc. Pls let me know what you think about the computer and what could help the oc. Here's the link to the computer on newegg. now that i know about oc'ing i would have probably chosen something different but it's fine for now. http://www.newegg.com/Product/Produ...&cm_mmc=TEMC-RMA-Approvel-_-Content-_-text-_-

Currently its running at 4.0 ghz, but after about 1.5 hrs of prime core 3 will have a rounding error. See pic below. None of the other cores have this probelm, and can run for 3-4 hrs w/ no problems. here is the only options that the bios has available to adjust and the settings that i have them on. I would also like to add that i have a frio air cooler that works great. http://www.newegg.com/Product/Product.aspx?Item=N82E16835106150

ai overclock tuner- manual
cpu ratio setting- 20.0
extreme pharse full power mode- enabled.
other options for this are
bclk frequency- 200
pcie frequency- 100
qpi frequency- auto this also has options for 6407mhz and 7kmhz
dram timing-auto
cpu voltage- 1.275 this shows as 1.245 in cpuz
imc voltage- 1.3
cpu pll voltage- 1.8
pch voltage- auto
dram data reference voltage on CHA- auto
dram data reference voltage on CHB- auto
dram voltage- 1.65
load-line calibration- enabled
pcie spread spectrum- auto this could be enabled or disabled also. idk which is best

all c1e and power saving freatures are off

memory checked out through memtest85, and is currently at 1600mhz

quick question, what is the computer being used for ? gaming or do you have this beast folding or some other type of DC ?

I might set it up for folding but for now its just for fun and for gaming. I just want to make sure that it has a stable overclock. I ran prime overnight and all the cores were perfect except for #3 and it made it 3.5 hrs before getting the rounding error. So the only core i have trouble with is #3. idk why.