Question Overclocking voltage confusion

Mar 16, 2019
7
0
10
0
I am overclocking an i5 8600k to 4.9GHz on an Asrock Extreme4 mobo with fixed voltage of 1.34v set on BIOS.

While stress testing, the overclock was stable with Prime95 non-AVX small fft (passed at 1hr) and Realbench (passed at 8hrs), HWinFO64 shows that my max vcore under load was 1.312v constasnt with jumps to 1.328v at max LLC setting (level 1 for this mobo). Temperatures maxes at 90s degrees.

I want to know where this vdroop is coming from, and does that mean I'm stable at using 1.328v instead of 1.34v as set on the BIOS and can lower it more? Because I once had a BSOD on 1.335v set on BIOS while running RealBench stress test.

Another issue I came with is the difference between using fixed voltage and offset voltage. Why is that for this particular clock speed, stress test requires a 1.344v+ to run stable on an offset voltage setting (I went up to 60mV and still failed), while I am stable for fixed voltage with lower vcore?
 

Lutfij

Titan
Moderator
Which BIOS are you on? What is your aftermarket cooler? Better yet, might want to include your full specs like so:
CPU:
Motherboard:
Ram:
SSD/HDD:
GPU:
PSU:
Chassis:
OS:

and state what the airflow in your case is setup as. I personally think your voltages are high, if you're using the BIOS(voltage) numbers as the baseline. You should use HWMonitor to help cross reference the voltage numbers.
 
Mar 16, 2019
7
0
10
0
BIOS version is P3.30 for AsRock mobo (think its the latest as I updated a few weeks ago).
The airflow in my case is set up with two Noctua NF-A14 chromax fans as intake on the front, and two Fractal Design Dynamic X2 GP-12 120mm stock fans (one at the back end, and one directly on top of the cooler - both as exhaust).

CPU: Intel i5 8600k
CPU Cooler: be quiet! Dark Rock Pro 4
Motherboard: AsRock Z370 Extreme4
Ram: HyperX Fury 2x4GB 2400MHz DDR4
SSD: Samsung 850EVO 120GB for OS drive
HDD: ST3500620AS (I really don't know the hdd, it's really old from a computer ages back)
GPU: RTX 2080 ASUS Strix Advanced Edition
PSU: Corsair RM750x (2018)
Chassis: Fractal Design Meshify C
OS: Windows 10 Pro

I just don't know if its a RealBench problem, but it seems that with offset setting, Realbench draws less voltage to run than Prime95. VID sometimes jump to 1.319 while the highest vcore with the offset setting stagnates at 1.3v12.
 
Last edited:

Karadjgne

Titan
Herald
VID is the voltage the cpu tells the mobo VRM's to supply. Vcore is the voltage that the cpu actually uses. Use offset at idle, not load voltages. For example: if your idle voltage is 1.256V and your VID is 1.3461, your Offset is -0.0901. Rounded by the 0.005V increment, it becomes 0.10V. So that is a negative offset, meaning you have to switch to the negative offset mode sign in order to subtract 0.10V from 1.3461V.

It is generally better to use the lowest setting for LLC that you can, especially when using offset. High settings for LLC can cause significant voltage overshoots when the load changes (how much that matters is open for debate) but more significantly, they can cause you to use too low an offset which results in crashes at idle or lightly loaded tasks. So lower LLC plus a slightly higher offset value is generally best.

Different apps can and will change voltages on the fly. RealBench is designed to do just that as it uses ram, cpu and gpu in different loads and amounts, which is what makes a stability tester. P95 isn't as good at that since it's loads are more static, especially small fft. And doesn't punish the system as a whole, including usb/pcie subsystems, just the cpu mainly with some ram usage.

Make sure the motherboard chipset drivers are also current, Win10CE updates can have a field day with what it considers legacy/outdated/lower version number drivers.

The hdd is a Seagate Constellation ES.2, that's an enterprise drive, pretty solid
 
Last edited:
Mar 16, 2019
7
0
10
0
VID is the voltage the cpu tells the mobo VRM's to supply. Vcore is the voltage that the cpu actually uses. Use offset at idle, not load voltages. For example: if your idle voltage is 1.256V and your VID is 1.3461, your Offset is -0.0901. Rounded by the 0.005V increment, it becomes 0.10V. So that is a negative offset, meaning you have to switch to the negative offset mode sign in order to subtract 0.10V from 1.3461V.
Wouldn't both vid and vcore be the same if its on idle? I tried it and cannot see a difference (also there's too many things in the background causing quick jumps whereas under load its steady). I was under the impression that you want vcore to be above the VID so why a negative offset? Sorry I'm still quite confuse on this statement here.

It is generally better to use the lowest setting for LLC that you can, especially when using offset. High settings for LLC can cause significant voltage overshoots when the load changes (how much that matters is open for debate) but more significantly, they can cause you to use too low an offset which results in crashes at idle or lightly loaded tasks. So lower LLC plus a slightly higher offset value is generally best.
While I agree on this part, Asrock's LLC seems a bit different than ASUS or Gigabyte's. Their highest level doesn't seem strong and in fact doesnt overshoot as much (and seems to still have vdroop still even under stress testing). Their second highest (level 2) seems to have too much vdroop and as you said will require more increase in voltage (which I thought is what we want to have less of).


Different apps can and will change voltages on the fly. RealBench is designed to do just that as it uses ram, cpu and gpu in different loads and amounts, which is what makes a stability tester. P95 isn't as good at that since it's loads are more static, especially small fft. And doesn't punish the system as a whole, including usb/pcie subsystems, just the cpu mainly with some ram usage.
I do use RealBench as my main stress tester, it's just that I can't find an offset setting that will allow it to pass this test despite already knowing a fixed setting that passed 8 hours of testing.
 

Karadjgne

Titan
Herald
Voltage under loads almost always drops. You want vid and vcore to be pretty similar, within 0.05v if possible. With vid offset set very high, you do nothing but punish the VRM's unnecessarily. So if VID was 1.3461 and vcore 1.256, then applying a negative offset of 0.1v would drop the vid to 1.2461v with a vcore of 1.256v.

Offset is not always positive and idle vid is normally higher than load vid.

With LLC, it's trixy. When you very first add a load, Vdroop causes the voltage to drop below the level of vcore you set. You can get around that by increasing vcore, but that just adds heat. LLC adds a little voltage, as needed, to maintain the vcore value. 0% adds the least amount of voltage, 100% generally overvolts aggressively, a small amount at load, but a much larger proportion at idle. Where it's totally unnecessary since idle is easy to maintain. Since most high OC has idle disabled, high aggressive LLC is fine, but plays havoc with idle vcore/vid numbers on mild OC with idle enabled. So for most OC, @ 50% is a good start, adjust up or down as needed. You don't really want to add voltage anywhere more than necessary as that does nothing but jack up cpu temps.
 
Mar 16, 2019
7
0
10
0
Voltage under loads almost always drops. You want vid and vcore to be pretty similar, within 0.05v if possible. With vid offset set very high, you do nothing but punish the VRM's unnecessarily. So if VID was 1.3461 and vcore 1.256, then applying a negative offset of 0.1v would drop the vid to 1.2461v with a vcore of 1.256v.
Doing that would drop the vcore more, are you sure you're not mistaken? That seems counter to what I'm trying to achieve..
 

Karadjgne

Titan
Herald
You seem to be under the assumption that you need to be adding high voltage everywhere. You don't. That's why you use idle (as in no loads running) vcore readings not vcore under heavy loads. It's higher. Then you offset vid to match. That way when you do open something or something draws instantly hard on vcore, the LLC can add enough to bring it back and maintain a more stable amount. The higher the OC, the higher the idle voltages, you are aiming to balance the difference. Using too high an LLC is only beneficial to heavy instant loads, that first kick, but it also adds to the idle voltages, so you end up with a higher offset. You want vid and vcore to be very close, that way the LLC doesn't have as much voltages to be adding. If that means using a negative offset or positive offset, then that's what you use.
 

Globespy

Commendable
Feb 8, 2017
10
0
1,520
1
Are you happy with BIOS 3.30 with regard to overclocking?
Did you use a previous version?
Is 3.30 more stable with same OC settings?

I have the same board, delidded 8086k.
I'm on BIOS 3.10, and to preface this, I won't likely buy another AsRock board.
They have the worst customer service, they don't answer in their own forums and even sub forums like here and tweaktowns, they ignore their customers.
Their adaptive voltage is absolute trash when you are looking to push a CPU to it's max (delid etc), and when you are pushing 5.3-5.4Ghz (what I'm running on the 8086K, all cores, no AVX offset), so fixed LLC1 is really the only way to get stable, at least on BIOS 3.10.
I use small 40mm fans to actively cool the VRM/MOSFET's, which is important when you water cool, you have Noctua air cooler so you are good :)

That being said, there is something you might want to look at in your OC quest.
Using HWInfo64 you will see that this board has 2 entries (in sensors) for Renesas ISL69138 controller.

One of these sensors is wrong, you can see that it's wrong, so hide it.
You can easily tell which one is correct as the first value 'VR Loop1' will correspond to a CPU Value 'VR VCC Temperature(SVID)' - this is essentially the VRM/MOSFET temperature sensors.
If you have a 'fixed' vcore in BIOS, the value below 'VR Loop 1', a value named 'VR VOUT' will be very close to the 'vCore' setting.

This 'VR VOUT' value is essentially a more accurate reading of the real voltage that the core is requesting from the VRM/MOSFET's - there's a lovely technical reason for this which involves resistance in circuitry that means 'vCore' is not the most accurate reading, and that's really all you need to know. :)
The author of HWInfo and AsRock have confirmed this sensor is indeed correct and should be trusted as a more accurate reading of core voltage.

As other's have pointed out (kinda in a roundabout way), if we are looking at fixed vCore, due to vdroop it's impossible to have the same fixed idle voltage as under load voltage.
And the higher the OC, the more voltage you need to push.
With Fixed vCore and LLC1, you will typically see idle voltage about 30mv higher than full load, such as stress test with Realbench (also my favorite).
So let's say my idle vCore at 5.3Ghz is 1.415v, under load the vCore value in HWInfo will pretty much stay the same, with occasional dips to 1.406v.
BUT, the VR VOUT value will be in the 1.386v area, which shows just how much variance there can be, and why even the tightest LLC on this board is still trash.

High voltage at idle is NOT dangerous in terms of killing your CPU - within reason of course. If you have nice cooling, you can sit at 1.45v at idle, with 1.41-1.42 under full load.
High idle voltage will barely draw any current (amps) or power (watts) - Coffee Lake processors are good for 138A/180W continuous, which even under stress testing conditions is very unlikely. You might see spikes, but not constant.

On the other hand, what can damage or degrade a CPU is High Voltage combined with High Current and High Power,.
This is why I've always used fixed voltages, and always turn off all C-States, Speedstep(EIST)/Speedshift - my PC's are primarily for high performance gaming, so I could care less about saving a few dollars a year, and quite frankly the environment has WAYYY bigger issues than me drawing a few more amps per month than another PC with max power saving settings.
There's many who have the opinion that higher idle voltages kill CPU's, but if you have good cooling and keep those temps in check (I'm at max 72C after 4 hours Realbench) then you will replace your PC long before your CPU degrades.
Now, if you are running vCore at 1.5v, then you will likely see degradation during the life of the PC, but even then it's still not a fixed science.
Stay under 1.45v idle and good cooling and if you replace your PC every 3-5 years you will most likely have zero issues.
I have never had a CPU die on me, 30 years of building PC's - and I'm not alone :)

So, this may help you feel a little more comfortable about raising the 'vcore' value in BIOS, because your under load value on this board is going to be quite a bit lower, and that's the one you really need to care about.

BTW - would love to hear if you like the new BIOS better.
I'm thinking of going back to 1.20 before all this Spectre microcode crap that has impacted performance, but most likely tossing this board in the trash.

Cheers!
 

Karadjgne

Titan
Herald
5.3/5.4 all core is pretty impressive. Especially at 72°C after 4hrs worth of handbrake.

And yes, I do wish mobo ppl would just all get together and agree on terminology. So much easier if everyone just called it vcore (voltage used by core) and VID (voltage in demand) and VRM temp and cpu temp etc. Start tossing around VR loop 1 and VR vout or tmpin1-6 and nobody has a freaking clue unless you go beating on someone else's door.
 

fahad9t

BANNED
May 12, 2019
50
1
35
0
if you are telling me ur temp is 90 when u stress it? if thats true kill me know
cpu modrate temp limit is 70 they say 80 but not evrything is true
if you are encountering windows crash thats not the problem with ur multiplier
its the voltage cpu dosent get enough so its shuts down
other thing is when overclocking try to bump or lower volts only by +2x/-2x try to find the coolest temp highest clock
disable any other cpu bios features like powersaving and cpu fan from auto to manual
anything that comes with cpu wich save power
auto volt and manual volt it should be auto if u dont overclock and u have prfomance boost enabled
manual volt dosent harm anything until prfomance boost is enabled. voltages changes with the frequency
but if u want constant eg 4ghz freq the volts wont change . and when boost enabled it will change fluctuate
 

Karadjgne

Titan
Herald
The volts change regardless of boost or not. A psu does not have the ability to reproduce a pure DC voltage, every voltage it can reproduce is subject to ripple, where the voltage peak dips according to the AC sine wave. Better psus have much lower ripple, but it still exists. VID is voltage the cpu demands the motherboard VRM's supply, vcore is what the cpu actually uses, the offset voltage is the difference. Voltages change according to loads and how much of that offset is applied, and thats where LLC comes into play. It's a constant up/down balancing act, where having too much LLC is a bad thing, especially on a low end, high ripple psu where voltage peaks/spikes are actually cut off, interrupting the voltage flow, and the cpu shuts down.

No such thing as a pure static voltage anywhere in a pc, although the best psus can come pretty close. Mostly it's just that reporting software only tests a few times per second, whereas the voltage is fluctuating 50-60x a second.
 

Globespy

Commendable
Feb 8, 2017
10
0
1,520
1
5.3/5.4 all core is pretty impressive. Especially at 72°C after 4hrs worth of handbrake.

And yes, I do wish mobo ppl would just all get together and agree on terminology. So much easier if everyone just called it vcore (voltage used by core) and VID (voltage in demand) and VRM temp and cpu temp etc. Start tossing around VR loop 1 and VR vout or tmpin1-6 and nobody has a freaking clue unless you go beating on someone else's door.
Personally I think VR VOUT should replace vCore given that it's a much more accurate sensor reading.
VR Loop is important too, as there's so many using AIO coolers and don't realize their VRM's are cooking, and can cause big problems in finding stable overclocks.
AsRock recommend additional cooling of the VRM/MOSFET when an AIO is used, but who reads manuals these days?

Not sure what my next board will be.
Asus boards are decent, but overpriced because of their brand name and all the ROG marketing stuff.
I want to like AsRock, since they actually build nice boards with premium components found in much higher priced enthusiast level boards at twice the price.
But their BIOS needs work, and their lack of customer service is just inexcusable.
 

Karadjgne

Titan
Herald
Oh, I agree they are important, just saying that VR VOUT should be labeled vcore or core voltage, and VR Loop should be labeled VRM Temp. Would make life so much easier if a user could actually just read what something was and ask 'is 90°C ok for VRM Temp?' instead of the mad scramble for ppl trying to decipher exactly what that represents in an ASR bios if it's called VR Loop.

You knew what VR Loop was, I dint have a clue since I've never used an ASR bios.
 

fahad9t

BANNED
May 12, 2019
50
1
35
0
The volts change regardless of boost or not. A psu does not have the ability to reproduce a pure DC voltage, every voltage it can reproduce is subject to ripple, where the voltage peak dips according to the AC sine wave. Better psus have much lower ripple, but it still exists. VID is voltage the cpu demands the motherboard VRM's supply, vcore is what the cpu actually uses, the offset voltage is the difference. Voltages change according to loads and how much of that offset is applied, and thats where LLC comes into play. It's a constant up/down balancing act, where having too much LLC is a bad thing, especially on a low end, high ripple psu where voltage peaks/spikes are actually cut off, interrupting the voltage flow, and the cpu shuts down.

No such thing as a pure static voltage anywhere in a pc, although the best psus can come pretty close. Mostly it's just that reporting software only tests a few times per second, whereas the voltage is fluctuating 50-60x a second.
am no expert bro but u can say i am medium experienced and
i never messed with so called vid voltage control ,v core
can i mess with that too ? can u elaborate what are the pros and cons of v core volt increase and low
 

Karadjgne

Titan
Herald
Cpu temps and higher speeds are proportional to voltages. Higher the voltage, the faster the cpu can run stably and higher the temp. Mostly.

Intel sets its stock values pretty high to begin with, since every cpu has different requirements, a higher starting voltage covers everything. So a low-mild OC can be achieved without changing much of anything.

The cpu has in its head a desire for a certain amount of voltage, so demands that voltage from the motherboard, this is VID. What it actually ends up using (according to loads) is the vcore. For lowest temps, especially on the VRM's, you'll want idle vcore to be within @ 0.05v of the VID. Basically it demands as little as possible, and only uses that much. That 0.05v is the offset voltage and can be + or - offset, depending on if VID is higher or lower than vcore usage. LLC is how aggressively that offset is applied.

So let's say you have VID of 1.32v and vcore (idle) of 1.16v. The offset is 0.16v. If you lower the offset to 0.08v, VID becomes 1.24v, so VRM's run slightly cooler and consequently less overall heat output. Conversely, if you bump speeds, you might need higher vcore to remain stable, so you could bump vcore from 1.16v to 1.30v and still be good. Temps just went through the roof.

It's a balancing act, trying to get the lowest overall heat output means the pc can possibly get higher OC out of the same cooler. So on a budget cooler like a hyper212 some ppl might see 4.3GHz at 1.32v, others might get 4.5GHz at 1.24v and run the same temp.
 

fahad9t

BANNED
May 12, 2019
50
1
35
0
thank you for the information
i have a fx6300 with a CM hyper h410r
its oced to 4.2 when stressed max temp is 65
and normal temp is 32 c
1.33 v i was previously on 1.37 the temp reached 80 after 10 min of stress
then i bumped down to 1.35 still max was 75
then again i lowerd it to 1.33 and finally i got stable 65 c when being stressed
and i have a good psu its corsair vs550w or smth i dont remember the first alphabet
 

Karadjgne

Titan
Herald
0.04v drop got you 15°C max difference. As long as you are still good and stable, that's a really good drop, but as you can see, because of the amount of temp drop, that cooler is pretty close to maxed out ability, just a little more power putting it right at the edge.

But that's a really good result none the less, those FX cpus aren't Intels and don't have the heat range. To really test what's left, and see just how close you really were to throttling, run AMD Overdrive. That program temps work kinda backwards to normal readings, it knows the max temp (read from the cpu info) and will tell you exactly how many °C you are from max. Normally, a 10ish °C reading is cutting it close, less than 10 means you need either lower voltages or OC, the 20's is plenty of room etc. Overdrive is the only recommended temp solution for those FX.
 
Last edited:

fahad9t

BANNED
May 12, 2019
50
1
35
0
0.04v drop got you 15°C max difference. As long as you are still good and stable, that's a really good drop, but as you can see, because of the amount of temp drop, that cooler is pretty close to maxed out ability, just a little more power putting it right at the edge.
yes my fan on hyper i changed bios setting of fan auto to manual at constant high speed
and i got 2 cabinate fans both running on a seprate 12v adapter not by pc power
and when i stress for 10 min and stop the temp drops fast like in 1 min its 35 from 65
do u think going below 1.33v would be a good idea?
can i tweak it more?
 

Karadjgne

Titan
Herald
Lower is always a good aim, that's part of overclocking too, getting best performance includes low temps.

Generally you'll keep going down until you become unstable, then kick it back up a notch and really test for stability. Asus RealBench is good for that. When you think you at lowest possible, run RealBench for @ 8hrs. If it passes, it's usually considered successful.
 

Similar threads


ASK THE COMMUNITY

TRENDING THREADS

Latest posts