Gigabyte Z270 Overclocking help

reindheart · Oct 16, 2017

Hey guys,

First time overclocking a CPU and I just have a couple of questions. I followed all the instructions in this overclocking guide for the Gigabyte Z270 series of motherboards https://view.joomag.com/gigabyte-z270-overclocking-guide-gigabyte-200-series-overclocking-guide/0767815001483933769 and managed to hit a stable overclock of 4.8ghz on 1.31 CPU VCore using Prime95. However I have a couple of questions.

1: How do I set up adaptive VCore? I'm not too sure about the full details of this but I heard somewhere that having my CPU at a steady high voltage can be bad for my CPU.

2: Is this a high voltage for a 4.8ghz overclock on the 7700k? I looked around the internet and alot of people seem to be able to get 4.8 under 1.31v. I understand that not every chip is created equal, silicon lottery etc, but i'm not sure where 1.31v stands in relation to my OC. I'm also running a Fractal Design S24 240mm liquid AIO.

3: When i'm idle, my CPU VCore as reported by HWMonitor is at 1.308, as I set it in my bios. However when I run Prime95, the VCore on HWMonitor drops to around 1.2~. Is this normal?

4: How noticeable is the difference in terms of gaming performance between 4.7 and 4.8ghz? With my CPU Voltage at 1.31 I'm getting temps in the high 60s to mid 70s, whereas with a Voltage of 1.26 at 4.7ghz I'm around the low to mid 60s - a temperature threshold I much prefer.

My motherboard is the Gigabyte Aorus Z270X Gaming K5. CPU is an i7 7700k and I'm running 16gb of 3000mhz Dual Channel Ram.

Eximo · Oct 16, 2017

I basically have that build.

Using a fixed vcore is usually what you do to find the CPU's limits and needs.

1) Now that you know the voltage, reset your BIOS to defaults. I used this guide, and it worked quite well. You can ignore the "Skylake" part, basically all the same rules apply, just that the CPU is capable of another 300Mhz or so. https://www.tweaktown.com/guides/7481/tweaktowns-ultimate-intel-skylake-overclocking-guide/index.html

2) 1.31 is fairly typical for 4.8Ghz from what I have seen.

3) This is known as voltage droop. Load Line Calibration can be used to counter-act this, but it will increase the maximum voltage used under load slightly.

4) Hardly noticeable difference. If you want to target temperature over performance, then that is basically the compromise you have to make.

geofelt · Oct 16, 2017

1. Adaptive voltage is a good thing.
It will reduce the multiplier and the associated vcore when the cpu has little to do.
The nomenclature varies but there should be such a tuning knob somewhere in the advanced functions of your bios. In windows power management, you also have to allow the cpu percent busy to drop from 100% to something lower.

2. 1.4v vcore is considered about the limit for an overclock.
As of 6/9/17
What percent can get an overclock at a somewhat sane 1.4v Vcore.

I7-7700K
4.9 83%
5.0 62%
5.1 29%
5.2 6%

4. run at a multiplier you are comfortable with. You will see negligible difference from 4.7 vs. 4.8
Of course, you have the wherewithal to do this comparison yourself.

Eximo · Oct 16, 2017

Here is a good chart from LTT that elbert found. Quite revealing for me, I always suspected I didn't get a very good CPU, but I overclocked this thing the first week they were out.

https://linustechtips.com/main/uploads/monthly_2017_05/5908f6728d607_aHR0cDovL21lZGlhLmJlc3RvZm1pY3JvLmNvbS81L1AvNjM5MTMzL29yaWdpbmFsL0NoaXAtUXVhbGl0eS5qcGc.jpg.d39cde6b8164d55e7f1ccab2c8bb4d18.jpg

reindheart · Oct 16, 2017

Eximo :

Thanks alot for your help, that guide looks very complicated but I have work soon, so I'll take a closer look at it once I get back. Just some quick questions, since I'm going for a 4.7ghz overclock on a 1.26 CPU Voltage, how would I go about setting the LLC so that my voltage scales with usage and doesn't run at max voltage even at idle?

Eximo · Oct 16, 2017

LLC only changes the scale at which the CPU increase voltage under load. The power saving features are completely separate. You could manually re-enable them, but it is simpler to start with a clean slate now that you know the CPU's rough traits.

geofelt · Oct 16, 2017

In windows power management, set the cpu busy limits to allow varying from say 20% to 100%

In your bios, I think maybe vcore = auto may really be adaptive.
Clear as mud.
Check cpu-Z.
At idle, the vcore and multiplier should be lower while under a stress test, both should be at max.

reindheart · Oct 16, 2017

Eximo :

So basically now that I know how much voltage I need for a 4.7 overclock, I go back to 'load optimized defaults' in my bios settings and only change the CPU voltage and Multiplier? I'm assuming the defaults automatically has the relative power saving modes/LLC automatically enabled.

geofelt · Oct 16, 2017

Be careful with "optimized defaults"
They are likely to be too aggressive.
Easiest to just increase the multiplier on all cores and leave voltage on auto.
You will get a reasonable oc.

Then find adaptive voltage or whatever gigabyte calls it.

Eximo · Oct 16, 2017

1.35 was the voltage default for an i7-7700k as I recall. That was with the original BIOS for the Gaming 5, I can't recall what it defaulted to with a BIOS update a few weeks later.

It isn't disastrous to run at 1.35 volts. But if you want to run 1.31, you can just set a negative offset, but that could drive it too low at idle. LLC is probably still necessary though, at least I found it so. Basically if you leave all the C states enabled the CPU will clock down when it isn't needed. You should be able to set the voltage leaving everything else on auto.

When I am home I can dig deeper into the BIOS settings. It has been a while since I poked around in there.

reindheart · Oct 16, 2017

Eximo :

If you wouldn't mind, I would greatly appreciate that. Thank you so much again for being able to explain a lot of these things to a complete newbie. I still have no idea on how to set an offset or adaptive vcore, but all in due time I suppose.

reindheart · Oct 17, 2017

geofelt :

Would I need to bother with LLC or things like offset values if I OC this way?

geofelt · Oct 17, 2017

reindheart :

I think not, at least for a modest OC.

Certainly more detailed settings of oc parameters can get you better results.
That takes more knowledge than I have.
The key is to monitor vcore with whatever you do and not let it go past 1.4v under load.

Eximo · Oct 17, 2017

I'm pretty sure everything is under a single menu for the CPU voltage settings. LLC is under Advanced Power settings. And the Advanced Frequency settings. That and XMP should be all you need. Setting the voltage while leaving the C states on should let it clock down. Windows has to be in normal operating mode and not 'maximum performance' otherwise it will stay at the boost frequency.

As usual the manual doesn't really do the live BIOS any justice. Vague descriptions of what everything is and few pictures. (And I am pretty sure they rushed these boards out, then rushed for X299 and Z370, so there likely won't be any updates)

That is why I like Tweaktown's guide. They not only show each relevant setting, but in five different BIOS. Was quite helpful for me since my last board was an ASUS.

reindheart · Oct 18, 2017

Eximo :

I loaded the BIOS settings to it's defaults, and changed only the CPU ratio (47 - 4.7ghz) and the Core Voltage (1.26) however when I run Prime95 my voltage is still below the 1.26v mark, whilst at idle/non stress testing its at 1.248v. Is this 'bad'? If so, which settings should I adjust to fix it?

geofelt · Oct 18, 2017

Look at cpu-Z at idle.
If you have implemented adaptive voltage and speedstep, your multiplier should be lower than 47 and your voltage should be less also.

If you can run prime95 @47 with vcore at 1.26, You have a very good chip and can do better if you want.

reindheart · Oct 19, 2017

geofelt :

I turned on LLC in my BIOS settings to Turbo and set my voltage to 1.24, at idle i'm at 1.248 volts and below 4700 mhz, but in prime95 under stress it goes anywhere between 1.248 to 1.284, usually hovering between 1.248 and 1.260. How does this look? Should I lessen my voltage even more to stop it from peaking up to 1.28?

geofelt · Oct 19, 2017

7700K is ok at up to 1.4v with a stress test.
You can do better than 4.7, but if 4.7 is comfortable for you, then you are good and need to do no more.

If, however, you do not see vcore less than 1.0 at idle, then you are not allowing the voltage to drop when there is little to do. That 1.2xx is not worrisome at all. The key to lowering it is to find the adaptive voltage/speedstep knob in the bios.

reindheart · Oct 19, 2017

geofelt :

I think I'm comfortable keeping it at 4.7, as I'm only gaming and not doing any productivity so I don't REALLY need the extra power. I'm having trouble finding how to set it to adaptive, my vcore is never less than 1.0 at idle. I have my C-States enabled, Speed shift enabled, and something called Voltage Optimization in my BIOS enabled as well. Under my CPU Voltage settings in my bios, I can either leave it on auto, set it manually to a value (which I have set to 1.260 volts), or set it to normal. If I set it to normal, it unlocks an option called Dynamic VCore (DVID) which lest me set that option to Auto, Normal, or a negative value. I'm not sure how to utilize this function however. My LLC is also set to Turbo.

geofelt · Oct 19, 2017

When you set a value to a specific number, that is what you will get.

I think you want to set your voltage to auto which is normally a safe option.

From your description, I would try setting voltage to normal and the subsequent DVID option to auto.
I think that might be another name for adaptive vcore.

reindheart · Oct 19, 2017

geofelt :

Just tried that, at idle core voltage is still 1.26 sometimes going up to 1.27. This is really starting to frustrate me, I might just leave it on 1.26 manually considering everything that I've tried so far.

Gigabyte Z270 Overclocking help

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