Prime95 one core failure

[kingfoot]

So my system;

ASUS Crosshair V Formula
AMD Phenom II X6 1090t
G.Skill Ripjaw series DDR3 1600 1.5v
ASUS Radeon HD 6950 DCII/2gb
Corsair 600w Gamer series
Corsair H60 (With added fan for a push-pull radiator system)

The current 100% stable setup;

3.8ghz@200x19.5x1.45v (with a .05+/- load variance)
2000mhz HT
DDR3@1600x1.55v

Core reaches 54c after 24h


I can reach 3.9 with the above settings, and pass a 10m prime95 6 Test run. Not ready to call that 100% stable until a 24h test passes.

Now, before I do a 24h test on that, I want to try to reach 4.0 to run a test and if I can't get that to reach the 2h test, then I will fall back to 3.9 for 24h testing.

Here's the issue;

I get the settings for the 4.0 going. All my HW monitoring shows it running right where I set it so no math errors when in OS. But then I startup Prime95 to run a blend test. About 30-45 seconds in, core04 (5th core) fails test1. All 5 other cores pass Test1 and begin Test2. After about 2 minutes Test2 begins to complete on the cores in random order and sometimes core03 (4th core) fails, sometimes it passes. All remaining cores pass up to Test10 before I stop Prime95.

Is this a physical defect? I read somewhere that upping my vcore is all that's needed. Unfortunately under load at 4.98v in the BIOS will place the .05 variance to nearly 1.55v which I should NEVER go over. So what's going on here? Why can't I hit 4.0 stable? People have reported reaching 4.3 stable with this chip. I realize there are variances and I'm not a lucky person in that regard. But I've yet to see someone with ample hardware and cooling NOT reach 4.0 minimum.

Just a note; the ram is running at the stock settings, manually input by me to ensure their reliability.

 

[kingfoot]

From what I understand, the LLC settings in the BIOS is adjusting how much variance is allowed by the voltage when the computer endures varying levels of load. By increasing to the max or high setting, it will be harder to actually set the vcore. I would have to lower the set voltage because increasing the range will bring the voltage closer to 1.55 or accidentally going higher. By tightening it I can set the voltage I want and not risk burning it out...

Or is my understanding of this off?

I've observed with LLC set to moderate; the voltage is set to 1.49v in the BIOS and when running the test, it peaks at 1.54v. When I reduced it to low, it stayed much closer to what I set, and I was able to set it at 1.5v and it wouldn't go above 1.52v. However at this level, that is a LOT of watts from the PSU. I'm still curious if the power supply being 600w is not enough. I've read that the Phenom series can actually use almost 200w when overclocked near 4ghz. And with my GFX using nearly 200w itself (being overclocked as well), and the RAM having 4 sticks. I wonder if 600w is enough now. My motherboard comes with an 8pin and extra 4pin hookup for a little boost in power for overclockers. So my next PSU will meet that requirement. The question now is, will I benefit more in overclocking if I buy it now, as opposed to later after future hardware upgrades. (This machine is the catalyst for future upgrades as I chose part specifically to accommodate that).

 

[ThrillerNstinct]

[strike]Is there any way to test an individual core? Can't figure it out in Prime95 settings.[/strike]

Ok I got Prime95 to run on specified cores by setting the process affinity in task manager and adjust the cores to run on to 1 when initiating the blend test. The 2 cores in question pass to Test10. So I'm relatively confident the hardware is fine. Which leads me to believe it's the voltage settings.

Adjust your LLC (load line calibration) in your bios settings to very high or ultra, I had a similar problem where two cores were showing errors, but my computer wasn't crashing. LLC with help with VDroop and fix your cores from showing errors

I had the very same issue and the changes to the LLC's seems to have done the trick. Thanks!