Hi captains,I already asked this question in the Tomshardware forums, but I'm not getting the right answers, and mostly getting answers to other questions instead of what I asked.I've been running my i5 2500K 4.5 at 1.35V stable for around 6 months now. But I decided to overclock further to 4.7 GHz because I got slightly better results in terms of smoothness. I first tried 1.39V, and BSOD'd after a few minutes with the 0x124 error. Then I tried 1.40V, perfectly stable it seems. Ran Prime95 for 6 hours with no errors at all. No crashes in FSX, no BSOD's, nothing. But unfortunately I got a problem. Sometime,s around 1 out of 5 boots, when I boot up my pc, it turns on, but doesn't POST, screen stays black, and shuts itself off after 10 seconds, and then reboots again. Well, this is something that my Asus board as always done sometimes and always succesfully boots the second time. But not this time, the screen stayed black, nothing happened, and after 30 seconds waiting I manually shut off my pc. Then I rebooted, and once I came up to the screen with the "American Megatrends" logo it said something like: "Overclocking failed! Please press F1 and change your settings." I really don't understand this, because it's stable in Prime95, and have no problems at all except for this. So I tried 1.41V, same problem around 1 out of 5 boots, then I tried 1.42V, still the same problem after around 5 test boots.In my signature settings are my specs, and here my overclock settings:OC mode: XMPBCLK: 100Multiplier: 47Memory frequency: DDR3 1600 MHzInternal PLL Overvoltage: EnabledEPU Power saving: disabledLoad-line: Ultra highCPU current capability: 130%Phase control: extremeDuty control: extremeVRM frequency: 370CPU voltage mode: manualCPU voltage: 1.42VDRAM voltage: 1.65VVCCIO: 1.1VCPU PLL: 1.9VSpread spectrum: disabledEIST: disabledTurbo mode: enabledAdaptive thermal monitor: disabledExecute disable bit: enabledCPU ID: disabledIntel Virtualization: disabledC1, C3 and C6: disabledI hope you guys can help me.Thanks in advance!

Reading this, I got somewhat comfortable knowing I'm not the only one.Especially seeing that you're running Z68 chipset.The problem is a known one, the double boot is a known problem since P67 chipsets came out. To add to that, having PLL Overvolt enabled makes the situation even worse. Sleep mode and double boot hang are things that happen often.If you disable it, you'll maybe have a stable overclock. But only maybe.To me it happens almost on every power up. Also is why I try to power up/down only once a day.Also pulling the battery out and the power cord, some say, is going to make double boots more rare.You just gotta try stuff around. It's the only way if you have the problem.Good luck!Sent from my iPhone using Forum Runner

So that makes three of us. My Asus P8P67 Pro and i7-2600K o/c to 4.7 GHz also does this but not quite as often as 1 in 5 boots.I just live with it.If you solve it lets us knowGood LuckPhil

Reading this, I got somewhat comfortable knowing I'm not the only one.Especially seeing that you're running Z68 chipset.The problem is a known one, the double boot is a known problem since P67 chipsets came out. To add to that, having PLL Overvolt enabled makes the situation even worse. Sleep mode and double boot hang are things that happen often.If you disable it, you'll maybe have a stable overclock. But only maybe.To me it happens almost on every power up. Also is why I try to power up/down only once a day.Also pulling the battery out and the power cord, some say, is going to make double boots more rare.You just gotta try stuff around. It's the only way if you have the problem.Good luck!Sent from my iPhone using Forum Runner

So that makes three of us. My Asus P8P67 Pro and i7-2600K o/c to 4.7 GHz also does this but not quite as often as 1 in 5 boots.I just live with it.If you solve it lets us knowGood LuckPhil

Also very happy that you guys have the double boot problem too. But fact is, when I was running 4.5 GHz 1.35V, I sometimes had the double boot problem, then it rebooted, and upon the second time it ALWAYS booted succesfully. With 4.7 GHz 1.40V - 1.42V however, it sometimes double boots, BUT - instead of booting the second time, it just doesn't post again, does nothing. I have to manually shut it off, reboot, and if it doesn't double boot again, I get to the American Megatrends screen and says an overclock has failed. What also sometimes happens, is that it hangs when starting Windows, ONLY after a double boot has occured. Do you guys have exactly the same problem? I mean, after the double boot it doesn't boot again and I get an overclock has failed error message. You guys have the same? And again, I only have this error message after 4.7 GHz+. And the strange thing is, it seems to be perfectly stable in OS, FSX, and Prime95. It surprises me that so many people are recommending Asus motherboards. It's got only one problem (the double boot problem), but it's a very big problem and annoying. If I upgrade to Ivy Bridge / Intel Z77, it's gonna be an MSI board all the way. So few people have MSI boards, and they have great scores and great reviews, and seem to be very stable. The reason I went for Asus is because everyone recommended it.

I tried to o/c mine to 4.9 GHz but it would not run for long before I got the BSOD regardless of the voltage etc settings. I reduced the o/c to 4.8 GHz but then I got regular boot failures and the o/c failure message even though Prime95 would run without any problems. Since I reduced to 4.7 GHz I get the occaisional boot failure, maybe once a week, and most times it reboots on it's own sometimes I have to reset it. I read in an o/c forum that not all processors will overclock to the same level and some will reach their limit before others, the limit on mine seems to be 4.7 GHz so I just live with it.I have used Asus and Gigabyte boards mainly but I did go down the MSI route once and will never again. The board I had gave nothing but trouble, the kind that you cannot properly identify and it eventually completely failed, the first ever for me. So I replaced it with a Gigabyte board which still runs perfactly in my neighbours PC some5 years on.Good luckPhil

I tried to o/c mine to 4.9 GHz but it would not run for long before I got the BSOD regardless of the voltage etc settings. I reduced the o/c to 4.8 GHz but then I got regular boot failures and the o/c failure message even though Prime95 would run without any problems. Since I reduced to 4.7 GHz I get the occaisional boot failure, maybe once a week, and most times it reboots on it's own sometimes I have to reset it. I read in an o/c forum that not all processors will overclock to the same level and some will reach their limit before others, the limit on mine seems to be 4.7 GHz so I just live with it.I have used Asus and Gigabyte boards mainly but I did go down the MSI route once and will never again. The board I had gave nothing but trouble, the kind that you cannot properly identify and it eventually completely failed, the first ever for me. So I replaced it with a Gigabyte board which still runs perfactly in my neighbours PC some5 years on.Good luckPhil

--- Disregard, read you sig already. --- Excuse me for not entirely understanding your post (due to small language barrier), but you said that the Gigabyte board is now running in your neighbours pc, so what board do you have at the moment?So it seems you get exactly the same problem as me. Every now and then my 4.7 GHz overclock fails to boot, but is very stable in OS, FSX and Prime95. Also my CPU seems to be very voltage hungry also, for 4.7 GHz I need at least 1.4V, and to minimize boot failures I need at least 1.41V - 1.42V. If I go any lower than 1.40V it BSOD's after a few minutes. I can also only run 4.6 on 1.385, any lower and BSOD. For 4.5 it seems to be running perfectly at 1.34-1.35V. There seems to be a very big jump in voltage "hungryness" after 4.5 GHz...

The Gigabyte board with the cpu and memory were surplus to reguirements when I upgraded so my neighbour bought the other necessary bits and pieces to build it up again to a fully working system which he still uses today.I changed from using fixed cpu vo;tage to offset mode which helped me reduce the voltage. I now use offset vltage of +0.080 which in CPUz shows a cpu voltage max at 1.392 during Prime95 test. I Google'd it to see what it was all about.Phil

lso very happy that you guys have the double boot problem too. But fact is, when I was running 4.5 GHz 1.35V, I sometimes had the double boot problem, then it rebooted, and upon the second time it ALWAYS booted succesfully. With 4.7 GHz 1.40V - 1.42V however, it sometimes double boots, BUT - instead of booting the second time, it just doesn't post again, does nothing.

Exactly!! This is fully correct, as I already mentioned in my previous thread. I never tested 4.5, but I ran on stock, 4.8 and 5.0. 4.8 and 5.0 are causing frequent double boots and lockups when double boot happens, and stock was still double booting, but continuing. Here 4.8 doesn't work without PLL Overvolt enabled.I too have to reset with the power button +6sec, then turn on and then it usually works without a problem.

What also sometimes happens, is that it hangs when starting Windows, ONLY after a double boot has occured.

Correct. Same thing.

nd the strange thing is, it seems to be perfectly stable in OS, FSX, and Prime95.

Correct. I am 100% stable in all those programs in Windows, but 5.0 is causing VERY OFTEN double boots. It's why I recently decided to lower to 4.8, now I have it only occasionally.Stop looking for the solution, there isn't any. All mainboards, MSI, Gigabyte, ASRock, ASUS, whatever xyz show such behaviour. P67 chipsets were the first ones, Z68 continues in the same fashion. It's nothing new, and we'll see when it's going to be solved. Right now, it's not. Is also the reason why I'm yet not planing an upgrade to IB - why even, if it has the same bug?

Exactly!! This is fully correct, as I already mentioned in my previous thread. I never tested 4.5, but I ran on stock, 4.8 and 5.0. 4.8 and 5.0 are causing frequent double boots and lockups when double boot happens, and stock was still double booting, but continuing. Here 4.8 doesn't work without PLL Overvolt enabled.I too have to reset with the power button +6sec, then turn on and then it usually works without a problem.Correct. Same thing.Correct. I am 100% stable in all those programs in Windows, but 5.0 is causing VERY OFTEN double boots. It's why I recently decided to lower to 4.8, now I have it only occasionally.Stop looking for the solution, there isn't any. All mainboards, MSI, Gigabyte, ASRock, ASUS, whatever xyz show such behaviour. P67 chipsets were the first ones, Z68 continues in the same fashion. It's nothing new, and we'll see when it's going to be solved. Right now, it's not. Is also the reason why I'm yet not planing an upgrade to IB - why even, if it has the same bug?

I'm extremely happy to hear this. Never new that all P67/Z68 had this behaviour, I always thought it was only Asus. But I'm just wondering what exactly is causing the double boots? The overclock?

But I'm just wondering what exactly is causing the double boots? The overclock?

Please use selective quote, stop quoting the whole posts. Apparently you don't have a mobile device.It's high overclock coupled with the PLL Overvoltage. I forgot real reason behind it, it has something to do with S6/S5 (turn off/sleep) if I remember correctly. It's also why S5 Sleep doesn't work correctly.

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Sorry for the quote thing. Well, if the Z77 chipsets will solve these kind of problems then I might upgrade later, because PCI 3.0 will also give better GPU performance form y GTX 580 I read (and other cards of course). Btw, just wondering if these double boots, hangs, could cause any kind of hard to my hardware?

Btw, just wondering if these double boots, hangs, could cause any kind of hard to my hardware?

Not really. It's nothing bad really. Only possibly a little strain on the PSU, but in the end, I really doubt.Z77 might solve it, but only time will tell. Be sure to check dozen of known forums, scanning them for those bugs.

The Gigabyte board with the cpu and memory were surplus to reguirements when I upgraded so my neighbour bought the other necessary bits and pieces to build it up again to a fully working system which he still uses today.I changed from using fixed cpu vo;tage to offset mode which helped me reduce the voltage. I now use offset vltage of +0.080 which in CPUz shows a cpu voltage max at 1.392 during Prime95 test. I Google'd it to see what it was all about.Phil

Thanks for the Offset voltage recommendation! I looked into it, and I managed to reduce my VCore significantly. I now run 4.7 GHz at only 1.38V. ;) I guess i just have to live with the double boot problem cuz it's normal it seems...

I now run 4.7 GHz at only 1.38V. ;)

You should be able to drop it even lower. I run mine @ 4.8GHZ running at 1.336 volts.

Ben, you are running a 2700K, don't forget that. I don't believe he can push it much lower, if even at all. Always worth a try though...