Question about overclocking

[simmerhead 885]

I am OC'ing an i7 2700K with an ASUS Maximus IV Extreme-Z motherboard. I've never been into OC'ing before and am doing a moderate OC @ 4.5GHz. Temps are all fine during 3 hrs of Prime 95, but what puzzles me after reading up on the subject after the fact is that I run with a pretty low voltage, just 1.250V. There seems to be a common conseption that 1.35V is needed for a stable 4.4-4.6GHz OC on the Sandy Bridge chips.

 

My question is this: Can I run into trouble using such a low voltage, or doesn't it really matter? Lower voltages will give lower temps, but are there any downsides?

[martin-w 3,234]

My question is this: Can I run into trouble using such a low voltage, or doesn't it really matter? Lower voltages will give lower temps, but are there any downsides?

 

 

 

It's referred to as the silicone lottery. All chips are different. Some overclock great at low voltage, some are pigs and require tons of voltage for a minimal frequency increase.

 

You have probably done very well in the silicone lottery, simple as that. No it's not an issue, it's a good thing!

 

Could be that after further use with the applications you ordinarily use, that some instability manifests itself. But that's no big deal, just a case of nipping the voltage up a tad if required, when required. 

 

Asus, and some other authorities, Intel included, no longer favour Prime95. It's a synthetic stress test, so not the same as the applications we usually run day to day. For example, you can be Prime stable for many hours but fail in something like Hand Brake in seconds. For this reason, it might be an idea if you ran something like ROG RealBench. This is a stress test based on real world apps, instead of a synthetic stress test. It's always good to run more than onbe stress etst to determine true stability.

 

 

Incidentally, this is how Intel determine the high end chips from the lesser, cheaper variants. They "bin" them. When a big disc of silicone is manufactured it contains many chips, they test each one for capability. The higher models go in one bin, the ones that don't perform as well in another. This is how you get, lets say, a 6600K instead of a 6700K. From time to time, when the lower models run out, Intel will make up the numbers by putting the higher performing variants in the lower level bin, and just lower the capability with a software tweak. This way, on occasion, you can get a gem. Usually though it's just down to the variation within a batch.

 

 

Basically, it seems like you have a great chip.

[simmerhead 885]

Thanks a lot Martin. Seems like you know what you are talking about.

 

Thanks for the tip about ROG RealBench. I'll certainly check it out!

 

I'll be running Prepar3D v3 at max settings for a while - might be a good stress test as well

[aentwis 61]

If your systems is stable at that voltage and clock speed, it generally means you have a good CPU. If you have stability issues with RealBench or IBT (careful with that one...), then you might want to up the core voltage a little. You certainly have a bit of leeway still.

 

I run my 2700K at 4.8GHz with the Noctua DH14 cooling it. It runs stably, but I did have to push the voltage up to 1.38V or 1.39V to keep it stable (I don't have the exact value in my head and cannot check while in the office). I really need to test it with something other than Prime95, but it hasn't blue screened or stopped on me in 3 years as far as I can remember. I must add that I turned off HT. It would be difficult to run at 4.8GHz with HT enabled. That would need a higher voltage and 1.4V was my threshold... It does what I want it to do and has done so well for the last 2-3 years without any problems so far. Maybe one day it will fail... and that day I will build a new one

 

I would love to build an i7-6700K into a system with a GTX980Ti and two SSDs and the OS on an M2 drive... unfortunately, that upgrade would cost me easily €2000 or more.

 

A

[martin-w 3,234]

Yes that's true. Switching off HT will drop the temps by 10 degrees and provide more OC headroom.

 

I wouldn't recommend IBT, it's vicious. It's based on Intel's Linpack, and I recall not even Intel recommend it's use these days, and they created it.

 

At the end of the day, we want a PC that runs the applications we run day to day, we don't build Prime95 or IBT PC's. That's not their normal function.

 

ROG RealBench as I said and also the Intel Processor Diagnostic Tool. Aida64 free trial is worth a bash too.

[simmerhead 885]

Thanks. I have always been running with HT turned off, simply because it has been of little use for flight simming.

 

I'd like to keep my old 2700K running for at least another year as I don't want to upgrade until I know the specs and roadmap of the new NVidia and Intel chips.