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Discussion Starter · #1 ·
So I got everything in my sig rig (Asrock Extreme3 Gen3, 2500k, Noctua C14, Corsair HX 750 etc) and I'm just trying to tune my OC. Brainstorming ideas and such.

I want it to be stable under these tests:

prime 1344, 45 min
prime 1792, 45 min
prime blend, 8+ hours
linpack, 50-100 runs

Prime blend is mandatory, failing that means throwing out the OC altogether. However, it'd be nice to not see any errors in any of the above tests. I don't plan to fold, but anomalies that happen tend to make me suspicious of my system stability, so I want to rule out CPU and memory. Main use is gaming.

Currently, I'm doing a prime blend run, its 4 hours in. 78C peak in an 18C ambient room, though the two fans on my C14 are running at 900rpm, and can be increased to 1200 should it be required.

47x100

1.415Vcore
Highest LLC
1.832 PLL
1.15 VTT
1.152 PCH
0.925 VCCSA

PLL Overvoltage ON
C1E ON
Speedstep ON
CPU Current and that crap set at 250

Notes: I randomly bumped VTT and PCH earlier in the hope that it wouldn't cause instability being too low.

1.405Vcore will fail prime blend @2.5 hours. Fails 1792 within 15 min as well.
1.410Vcore will fail prime 1792 in 0-30 min. Haven't tried other tests such as blend.

Questions:

When people say 1.4Vcore max on air, 1.45V max on water, is it just because water generally cools better? If I can cool my CPU fine at 1.45V, would it be fine?

What other settings can I change in BIOS to squeeze every last Mhz?

What settings other that Vcore has a direct effect on CPU temps? CPU lifespan?

Is there any way I can drastically reduce Vcore and have the OC remain stable? I find that my CPU overclocks improve linearally by the amount of voltage I give. I plan to tinker with PLL voltage later.

Edit: Another question: Is it a good idea to play games while priming? Lols.

Thanks in advance for reading this masssive wall of text
smile.gif
 

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47x with 1.41vcore is a lot of voltage. But every single chip is different. I've had chips that can do 5.0GHz with 1.4v, and some that does 4.5Ghz with 1.375v.

Every chip is different. It's the luck of the draw with SandyBridge.
 

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Discussion Starter · #5 ·
Quote:
Originally Posted by bennoculus;15206337
47x with 1.41vcore is a lot of voltage. But every single chip is different. I've had chips that can do 5.0GHz with 1.4v, and some that does 4.5Ghz with 1.375v.

Every chip is different. It's the luck of the draw with SandyBridge.
Yeah, pretty much. If it weren't for my core #0 I'd actually have a golden chip
frown.gif


But on the bright side, I'm not one of those people who need 1.4V for 4.5
redface.gif

Quote:
Originally Posted by feznz;15206524
http://www.overclock.net/intel-cpus/1120291-solving-fixing-bsod-124-sandybridge-read.html
I am at the same stage but I am going to start with first a new install of os I can get 5Ghz bench stable for an hour but I have lost the count of bsod that could be the root of my problems ie corupted os
Hrm, I can actually boot to Windows at 5Ghz just fine. I rarely get BSODs of any sort, only when my voltages are obviously way too low. Stabilizing 5Ghz i think is impossible though, prime blend fails instantly even at 1.465Vcore and bumped chipset voltages.
Quote:
Originally Posted by Modz;15206565
Turn C1E and speedstep off!
I thought SB was made to be OC'd with them on?
 

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Try running PLLv at 1.70-1.76v
PCH doesn't need to be that high
Don't touch vccsa at all

My 2500K needs 1.428 vcore at 47x, 1.74v PLL, 1.14v vtt
 

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Discussion Starter · #8 ·
Quote:
Originally Posted by SMK;15208919
Try running PLLv at 1.70-1.76v
PCH doesn't need to be that high
Don't touch vccsa at all

My 2500K needs 1.428 vcore at 47x, 1.74v PLL, 1.14v vtt
Yeah, I'm testing lower PLL right now, around 1.6xx. Seems stable enough, 1792 BSOD'd after nearly 2 hours, but I don't think I could run into errors in normal usage.

Any other suggestions/answers to my questions?
 

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Quote:
Originally Posted by Kanashimu;15208107
Yeah, pretty much. If it weren't for my core #0 I'd actually have a golden chip
frown.gif


But on the bright side, I'm not one of those people who need 1.4V for 4.5
redface.gif


Hrm, I can actually boot to Windows at 5Ghz just fine. I rarely get BSODs of any sort, only when my voltages are obviously way too low. Stabilizing 5Ghz i think is impossible though, prime blend fails instantly even at 1.465Vcore and bumped chipset voltages.

I thought SB was made to be OC'd with them on?
Sounds like a pretty average chip, probably not just the overclocker.
 

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Quote:
Originally Posted by Kanashimu;15227568
Yeah, I'm testing lower PLL right now, around 1.6xx. Seems stable enough, 1792 BSOD'd after nearly 2 hours, but I don't think I could run into errors in normal usage.

Any other suggestions/answers to my questions?
no need to run 1792 for 2 hours. 15/30mins is more than enough, then a custom blend with your available memory for 12hours is fine.
 

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Most SB CPUs can do 4.7-4.8GHz, very small percentage can reach 5.0GHz, I'd say you have a pretty good chip.
 

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Your pushing for alot of Speed there with 4700 MHZ. and that VCORE isnt really safe for 24/7 use imo.
 
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