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xXCrossfireXx

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So here's my scenario:

• I want my chip to overclock to 4.7 GHz

I want at LEAST 5 years out of this chip

• My PC isn't on 24/7. It'll be on 4 hours maximum week days, possibly more on weekends at most for daily use, unless I leave it on once in a while to render/video edit

• I have an NH-D15 cooler

• I plan to do some gaming, and some video editing

So far my chip is at 1.365 volts, and it couldn't survive Prime95 @ 4.7 GHz for 30 minutes. So I definitely want to bump up the voltage to stable it out. But is 1.4 volts safe for what I plan to use this PC for?
 
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I'm going to have to ask for your help to expand on that a little. I'm no expert, but I've done a bunch of overclocking and followed numbers of different guides over the years. I've never, ever seen anything referring to testing the "audio system load." RE "video system load", of course graphics stress testing is important if you're OCing the graphics card, but this a CPU overclock he's talking about. If there's something I (and OP) are missing here, please would you link a guide, article or explanation so we can learn.

That is more voltage than I use to overclock my...
That NH-D15 you've got is at least as effective as most liquid coolers on the market.

4.7Ghz is around about the upper limit for plenty of 4790Ks though. I'd really question the value of going to such a high voltage for such a small performance gain. What voltage did (or do?) you need for 4.6Ghz? Usually once you approach the limit you start needing massive jumps in voltage for tiny jumps in frequency. That's usually where it's best to stop. There's 2% difference between 4.6 & 4.7 -> worth that much extra voltage?

If you really want to push as hard as you can, just try it for testing and benchmarking. Record your settings and temps as you go. It's safe and fine for testing/temporary benchmarking. Record what you need a stable for 4.6 versus 4.7, then you can make an informed decision about where you want your final 24/7 OC to be.
 

xXCrossfireXx

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I CERTAINLY do not need that much voltage probably, I'm almost hitting the stable mark at 1.36 volts. 1.38 is probably the most I'll need ;)

All I want to make sure of is that the 4790k will last me the given time.

EDIT: My chip hit 96 degrees at one point in the stress test, gonna try 1.34 volts, 4.6 GHz
 


Love this sentence! :)

You won't actually know until you try it. Ian Cutress from Anandtech only needed 1.3V for 4.6Ghz, but required a massive 1.45V for a stable 4.7Ghz: http://www.anandtech.com/show/8227/devils-canyon-review-intel-core-i7-4790k-and-i5-4690k/2
Once you start hitting the upper limit you need big voltage jumps... you won't know until you try it.

That's why I'm suggesting you try it, record your results, look at your temps & voltages and make an informed decision with all the information in front of you.

I think what I'm trying to say is that the voltage required for the lower frequency matters too. For me personally, for example, if I already needed 1.36V for 4.6, but 1.37V netted me 4.7, then I might go for it, it's only a small increase. However if 4.6 was stable at 1.3V, then I probably wouldn't bother with 4.7 once it required more than 1.35... all that extra voltage and heat isn't justified (for me - others would no doubt have different ideas).

Have a look at what Ian does with his tables in that Anandtech page I linked above. I think that's the best way because you have the information in front of you and can make a decision then.
 

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Like I said in my edit, I'm sticking with a lower voltage at 4.6 GHz. It won't affect my performance too much to have it at 4.6 will it?
 


At best, when you're not limited by cache size or memory, your CPU scales linearly with frequency. So if you do the maths it's just over 2% difference.

So just to clarify. When you say Prime95 "couldn't survive" are you talking a crash/error? Or do the temps get too high and it throttles? If it's the latter, then raising the voltage makes it worse... (sorry if I'm stating the obvious here, it's just worth clarifying in case). Higher voltages increase stability at the expense of heat. So high temps mean you need to lower the voltage, and if you can't get it stable at a lower voltage, then you need to drop you frequency to compensate as well.

BUT... are you aware of the issues with Prime95 on Haswell chips (like yours)? All recent versions of Prime95 (28.5 and later) use the AVX/AVX2 instructions on Haswell which creates significantly higher temps then you're likely to ever see in any other workload. Easily 10 or 20 degrees higher than other stress tests, let alone "normal" workloads. Lots of people have stopped using Prime95 or use an older version to stress test on Haswell for this very reason. People argue about what constitutes a "stable" OC... but my personal view is that the AVX2 loads of Prime95 are completely unrealistic. I would consider my OC stable even if it couldn't maintain safe temps under that sort of a workload.
 

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Holy crap awesome, that means my CPU was at 70-80 degrees in reality then at 1.38 volts. The issue wasn't temps, the issue was a watchdog timeout, that's what the blue screen told me anyway :p
 

Okay - so you got a BSOD when stress testing then? That's a sure-fire sign that you need more voltage. In which case I stand by my suggestions above. Prime95 is still super effective as testing stability, it just results in much higher temps.
 


Then do not overclock it as there is absolutely no need to overclock it for what you are doing with it.

When we overclock, it is knowing we are shortening the life of the CPU, and you want yours to last 5 years?

You have already shortened it's life from what you have done already, expecting any CPU overclocked to last 5 years is way past what they are even warrantied for at stock speeds, so good luck with that! :pfff:

Looking at what you've done so far overclocking you are just taking shots in the dark, because you really do not know what you are doing, and that is the best way to cripple a CPU, or seriously corrupt your HDD and Operating System.

FYI: Prime95 26.6 Stress Test, (what you should be running with a 4790K), is not an arrival at stability just because you can run it for any amount of time, as it does not test the Video and Audio system load, it is only the first step in reaching a 100% stable system.

The rate you are going forget the 5 years!

Edit: One last comment regarding your thread title, "1.4 volts for 4790k?"

That is more voltage than I use to overclock my i7-3770K Ivy Bridge CPU to 5ghz, and there is no way it will last me any 5 years, even with the cooling I run!

I am not trying to offend you, I am trying to get you to think, if you really need your CPU to last anywhere near 5 years, back off now!



 

So why don't you give some constructive suggestions?

Shortened it's life from some stress testing at 1.38V? Seriously? Have you actually had CPUs die young as a result of 1.3-1.4V OCs? There are loads of people running 2500Ks & 2600Ks that have spent their whole lives in the high 4s or even 5Ghz. Technically you're pushing them harder. I'm still running an old i5 750 that has spent most its life OC'd. Of course this is all anecdotal, but to suggest he won't get five years out of a CPU because he's considering putting 1.3-1.4V through it is pretty alarmist IMHO.

Also - what has the "video and audio system load" got to do with OCing the CPU?

You've got an OCing badge, so clearly your contributions would be really helpful to the thread, just looking for constructive suggestions here, that's all.

**Edit - I started my response during a game and didn't check for your update before posting - so there you have some advice at least :)**
 


 

xXCrossfireXx

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Um I've seen threads where people are asking about 1.3 volt overclocks, and in some cases more for 24/7 4790k use over 5 years and seen yeses, if you're telling me that my chip won't last 5 years, 4 hours maximum a day on a 1.36 volt overclock, that's just nuts
 


How could you even consider that as just nuts! when no 4790K has even seen 2 years yet since it's release date.

I've already told you it is not necessary to overclock the 4790K for what you use it for, if you are expecting it to last 5 years.

Obviously you're going to do what you want you just want someone to say it's OK, and I am not saying that, So Good Luck!

 
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I'm going to have to ask for your help to expand on that a little. I'm no expert, but I've done a bunch of overclocking and followed numbers of different guides over the years. I've never, ever seen anything referring to testing the "audio system load." RE "video system load", of course graphics stress testing is important if you're OCing the graphics card, but this a CPU overclock he's talking about. If there's something I (and OP) are missing here, please would you link a guide, article or explanation so we can learn.

That is more voltage than I use to overclock my i7-3770K Ivy Bridge CPU to 5ghz, and there is no way it will last me any 5 years, even with the cooling I run!
With respect, you don't know that. Sandy Bridge CPUs have just turned 5 years old and there are heaps of people who have been running them happily at 4.8-5Ghz+ since launch (I know a few!) Maybe they're lucky, I don't think we have any reliable data on life expectancy of OC'd chips to know for sure. But saying there is "no way it will last me" 5 years is just not accurate IMHO.

Having said all that, I re-read all your posts and I take your key point... if OP needs the CPU to last 5 years +, why OC in the first place? It's certainly a fair point.

OP - for what it's worth, my perspective is that I think you'd be unlucky to have a chip die on you if you settle for an OC before the voltage starts to ramp up steeply, which is what I've been advising from the start. Having said that, I fully concede that even that sort of an OC (maybe 1.25-1.32V) will for sure work your CPU harder and reduces the likelihood of it lasting the five years you want it too. Others like 4Ryan6 are obviously much more sceptical of the ability of an OC'd CPU to last that amount of time. No one can say for sure. In the end of the day you'll need to decide whether the risk you're taking is worth the extra performance you're gaining... which is, when you're already starting with a 4-4.4Ghz 4790K, actually pretty small anyway.

I'm happy to do my best to give my perspective on any further questions if that's helpful. Good luck.
 
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xXCrossfireXx

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Thanks, decided to back down and feed it 1.32 volts at 4.6 GHz. I haven't stress tested it yet, but so far no BSODs.
 


http://www.tomshardware.com/forum/id-2345618/reaching-cpu-overclocking-stability.html

FYI: Before I invested the actual time to write the information above, it was commonly shared knowledge between some of us that have overclocked for years at Toms Hardware, way back before we were blessed with all the unlocked multiplier CPUs we have today.





 


I've crippled CPUs and GPUs regarding voltage in my overclocking history, so I know full well what can happen.

CPUs are warranted based on a timeline of the stock voltage they are spec'd to run, it is a theoretical basing on stock history because even the CPU manufacturer has not had the 3 years for the fresh boxed CPU out of the factory door to be fully guaranteed all of them will reach 3 years and beyond.

The CPU stock voltage is set well within safe parameters, projecting a MTBF (Mean Time Before Failure), well after the warranty period is out, that is if the CPU is actually run at stock voltage settings! (Which is additionally taking into consideration the variances between motherboard auto voltage differences.)

Failures actually became in Intels best interests to sell additional overclock warranties that could be purchased separately, why?

You don't expect Intel to publicly post how many CPU failures come back to their doors do you, that would be bad for business, but there is good reason Intel sold additional overclock warranties.

Because Intel knows full well additional voltage supplied to the CPU shortens the MTBF, we in the overclocking world, I mean long term overclockers, have known that overvoltage past stock settings shortens MTBF for years and years!

However we accept that shortened life of the overclocked component as acceptable loss to enjoy the extra speed and performance we get from overclocking.

Most here at Toms are not concerned with how long a CPU lasts, they just want to know how far they can push the overclock, but in this thread the OP needs his CPU to last 5 years and that sir is 2 years past the 3 warranty of the CPU.

There are no guarantees you can give xXCrossfireXx that overvolting his CPU will even last the 3 years it is warrantied, much less an additional 2 years past that point, and it is highly irresponsible IMO to suggest otherwise.

http://www.tomshardware.com/forum/274139-29-electromigration

Electromigration is usually the cause of premature over volted CPU or GPU failures, and over volted is any voltage past stock settings.

However the further past stock voltage settings you go, the greater the damage occuring during operational run times , plus increased voltage equals increased heat, which is the secondary failure accelerator.

Computronix Intel Temperature Guide, does not cover CPU failure but is excellent information regarding Intel CPU Temperatures using ambient cooling.

It is a great reference to see a Intel CPU voltage ~ temperature relationship.



 


I am curious OK?

You said you need your CPU to last 5 years?

Why do you think you need to overclock it at all?

Where is it falling short in anything you are doing with it, that you feel it needs to be overclocked?

 


I understand and agree with all of the above. And if you read every one of my posts you will never find me giving any "guarantee" of anything regarding the life of the CPU. In fact, I've been encouraging him to find a lower voltage from my very first post.

In my experience it's not unreasonable to get 5 years out of an OC'd CPU. But obviously you've had different experiences. That's fine. I do totally take your point about questioning whether it's worth overclocking, given the pretty small benefits OP is likely to see. In the end OP will need to decide whether he or she is prepared to push the CPU harder and shorten the life.
 


Personally, I am all about pushing the overclock as far as the cooling will allow it to stably be pushed, with no regard for longevity, it's very rare anyone asks for overclocking advice and is expecting the CPU to last longer than it is even warranted.

I commend you attempting to get the OP to lower his voltage that at least would lessen the danger, if he is absolutely determined to overclock it anyway.

Thanks! Ryan

 

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Is there something wrong with 1.32 volts?
 


No, and for an overclock it's a fair bit of voltage, but not right on the upper end. It will absolutely reduce the life of your CPU. 4Ryan6 and I have differing ideas about how much risk there is that an OC like that will prevent your CPU lasting 5 years. But for sure the risk of a death within 5 years is much higher. The other question 4Ryan6 raises is: do you actually need to OC? If it raises the risk, it begs the question is it reward worthwhile? A 4.6Ghz OC is only 5% faster for lightly threaded workloads, and about 15% faster for heavily threaded workloads. So you need to decide whether that amount of performance gain is worth the risk of pushing your CPU into an early grave... it's up to you.
 

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I reduced the voltage even more to 1.308 volts actually. It survived a 1 hour 21 minute stress test (I turned off the stress test, it probably could've gone longer)

How's that?
 
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