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e8400 OC question

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Trent

Member
Joined
Oct 15, 2002
The build is in my sig, Im no stranger to OC'ing but this is my first intel build since the days of P3's. My e8400 will run at 3.6ghz (8x450) all day long at 1.22 load vcore, run 12+hrs orthos blend test stable at ~53c load. When I crank it up to 4ghz (9x445) on 1.35 load vcore it is small fft stable for 6+ hours(longest Ive let it run) with load temps approaching 60c, but running the blend tests cause it to error out in ~30-45min.

Now, the memory is run @ 2v and obviously Im having a hard time believing its the CPU or Memory causing the 30-45min stress error when in the 8x450 config the system will run 12+hrs stable and at 9x445 the cpu will run 6+hr stable on small ffts. So this leaves the NB/SB as culprits for causing the errors in my mind.

I have the NB volts set to 1.26 and the SB volts to 1.2, what is the safe maximum to run through the p5q pro, and do I have them set too low to be running 4ghz? Any other ideas to get blend test stability caught up with cpu stability? I dont want to push any more vcore through the chip and Im at the limit of where I am willing to push the load temps.

Thanks
 
Are you using stock cooling on the chip? If you are, I would suggest better aftermarket cooling. As for the ram, 2.1v is safe. It's @ 2.2v and above you need to be concerned about. Alittle extra voltage to both SB/NB is not going to kill the board. Just be sure you have good airflow over the them.

Every board/chip is different, no two are created equal. Some exact setups may need more/less voltage to attain the same clocks.

Just play with the voltages to your ram, SB & NB and see if it'll pass prime. Keep your eyes on the temps.
 
I reused a scythe infinity cooler from my previous AMD build and am not looking to replace that right now (idle temps @ 4ghz are ~35C load 59C & at 3.6 its 33C idle / 50C load). The core temps @59C are as high as Im willing to let them go, and 1.35vcore is as much as Im willing to put through this chip, so if I cant find overall stability Ill probably just stick with running at 3.6 @ 1.22v.

I wouldnt think the ram would need more voltage to run at 4ghz vs 3.6ghz when its running at 450mhz for 3.6 vs 445mhz for 4 but if I cant get it stable from the bridges Ill pump a little more through them.

I guess Ill just go with the original plan and mess around with increasing the bridge volts when I get home, because I can only figure those are whats giving the stability issues in orthos. All the C1E, Vanderbuilt, spread spectrums, etc are all disabled and such as well.
 
What about the cooling on your northbridge?

I had similar problems when overclocking my Q9450. I could run prime95 small-FFT's x 4 all day every day at 450 x 8 on all-stock volts, but it would choke after a short while on blend tests -- and would crash almost immediately when running a 3D game (crossfire 3870's at the time)

Turned out that four memory chips, a quad core processor and two video cards was just a bit too much for ye ol' X38 chipset to deal with at a 35% overclock. I bought a 60mm fan, strapped it on the bit fat NB heatsink and suddenly all was well -- no additional voltage was needed.

Give it a try by pulling the cover off your case, sitting some random big fat fan on top of your video card and aiming it at your NB sink. That's how I discovered the problem...
 
Its the stock cooling on the NB, but I can run blend tests all day at 8x450, but not 9x445 only small fft's. NB temp peaks at like 31C.
 
Sounds like a simple case of not enough voltage, normaly failing a blend is a sign of memory but you already know it can do slightly higher perfectly stable.

Give it some more voltage and see if it helps, you said you don't want more vcore but its not like you need to leave it there for 24/hr use, just more of a stability run, even Intel says 1.365V is safe, and their numbers are always consevative.

Most E8400s need upwards of 1.4V for a 4ghz OC afterall.
 
I'd say it's either NB or RAM. Try giving either more voltage, but I'd try the GTL Ref settings first to see if they help.

Also, I've read that the OCCT-RAM (2hr) test is better at isolating NB/RAM issues than Blend. I'd also make sure your memtest stable for at least 2 passes.
 
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