Can any OC experts explain to me clearly what VID is?

keith12

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Hi all,

As the title says, I'd like to understand better what part VID plays in OC'ing. I had always assumed that it was the defined voltage for running a particular CPU at it's stock clock, and fully stable.

An example being my recently retired Q6600 (GO stepping). It had a 1.3 VID, so when I OC'ed it, i began at that voltage and increased as needed to achieve my OC. A baseline voltage if you will.

However, I'm currerntly OC'ing my Ryzen 1600x, and its VID is 1.375. Yet I can get a moderate OC of 3.75ghz on the Ryzen (not really pushing yet at all), but with a voltage of 1.325!

If i decreased the voltage on the Q6600 below it's VID, then it would crash, and was obviously unstable.

Yet the 1600x at 1.325 was solid stable Prime95 for over 2 hours, with max temps of 69 degrees.

Hopefully someone can explain VID a little better, so I can rule it out as a variable for my current OC.

Thanks
 

shrapnel_indie

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LLC, or Load Line Calibration, is used to combat Vdroop (as it tends to be labeled), which is where voltage drops a little as power demands go up. When set right it makes sure Vin (or Vcore in older cases, the way I understand it) is compensated to counter that voltage droop as closely as possible, to keep your CPU operating stably while overclocked. Too little, and your CPU could become unstable under heavy load. Too much and you run the risk of over-volting.

Here is some more reading on the subject:
https://linustechtips.com/main/topic/24019-load-line-calibration-why-overclockers-should-care/
https://www.msi.com/blog/why-llc-is-your-friend-when-overclocking
 

saint19

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Hi and welcome to Tom's forum.

Lets see....

The CPU VID setting establishes the absolute maximum allowable processor supply voltage experienced during transient conditions and is not the target idle voltage.
 

keith12

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Thanks for taking the time to answer.

Okay, so by that account, when I'm OC'ing, does that mean I should not go beyond 1.375 vcore?

What the relationship between VID and Vcore?


 

shrapnel_indie

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That is correct. Do not exceed that voltage. You risk losing your CPU fast if you do.




VID is maximum voltage, it's usually a fixed value that Intel has decided is the maximum safe voltage.
Vcore is variable and is your actual operating voltage. It can change as needed (when the UEFI BIOS is set up to do so) along with your clock frequency depending on demand and thermals. When you overclock, you set the maximum/normal operating clock speed (outside of boost speed if activated.)

 

TJ Hooker

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Err, VID is definitely variable (with frequency/power state). VID is the nominal value the CPU is requesting from the VRMs based on current operating conditions. Vcore is the actual voltage at the CPU cores.

IIRC, VID is basically overridden if you're setting voltage yourself.
 

keith12

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Okay, thanks. That's much clearer now.

So, when I OC'ed at 1.325 @3.75ghz, it was stable. Does that mean I can potentially go lower on the Vcore? I will obviously try that, and see. But want to be certain enough first. I suppose under-volting won't kill the CPU, but not being an expert, this is all new territory and want to be safe. Or should I stay at 1.325 and maybe just up the CPU to 3.8/3.9 and see how it goes? Then if I hit stability problems at the higher clock, raise it to 1.350 and then 1.375 max?

Sorry, lots of questions.......agghhh

edit: on my first attempt, I just chose 1.325 as the Vcore, as I thought 1.375 (VID) was a high starting point for an overclock. Thats why i'm wondering if I can go even lower, and what the min value for Vcore might be. But the min value doesn't really matter does it? Because conceivably it could be any value (well within reason) that would allow the CPU to work at it's default clock speed.

Jeez, every time I write a reply, it brings a new question to mind :)

 

shrapnel_indie

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Yeah, it can change with frequency and power state, but outside of that, it doesn't change. and is usually the maximum you want to set Vcore for. (actually, you do want to operate under it if at all possible.)
 

keith12

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Lol, okay, am confused a little. It's fixed or it isn't?

But what you've said makes sense, at least to a layman. So, when people are OC'ing their CPU's, how do they figure out a baseline to work from? You'll see in my last post, that I simply chose a lower Vcore because the VID (i thought) was quite high. Fortunately enough, my moderate OC was complete stable at that Vcore (1.325). Is it so 'hit and miss' or is there a more clear defined approach to OC'ing.

I'm an ABC, 123 kinda guy. So if it's laid out in terms of a process to follow, then it really easy for me. If it's almost arbitrary, and not defined, then I get confused.

Hope I'm making sense, and it's not too trying to figure out a respone! :) Thanks again to all for the replies.
 

shrapnel_indie

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You might be able to go lower, or get a higher clock rate. It's hard to tell until you try. You'll know you hit the limit for that voltage and/or clock speed when things become unstable. Keep an eye on temps as well as stability. Of course, if you're happy with performance as it is right now, there's no harm in stopping there either. It's your call.
 

saint19

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What cooling are you using?

Basically you can lower the voltage as much as stability allow you. You can try lower it more and test stability, regarding this, 2 hours test is not enough. My last test for stability was 28 hours on y-cruncher. More important is test the rig on normal use, games, internet...all those stuffs that you daily do in your rig.

Safe voltage? Well I usually go high on this...I will go until 1.45V with good cooling off course.

What happen with CPU life? Lets see...

1) Usually you never had a CPU until it die, you sell it or give to a familiar for a basic rig.
2) The degradation could be 10-15%...with a CPU life of 10 years, so, you would lose around 1 and half year...you have CPU for another 8.5 years that, pretty sure, you will not use.
 

keith12

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You might be able to go lower, or get a higher clock rate. It's hard to tell until you try. You'll know you hit the limit for that voltage and/or clock speed when things become unstable. Keep an eye on temps as well as stability. Of course, if you're happy with performance as it is right now, there's no harm in stopping there either. It's your call.
[/quotemsg]

Thank you. Your posts are both informative and very clear. I will keep going, and have a better understanding of where my vcore should be, and how to progress further.

As a matter of interest, where does LLC come into play with higher OC's. I've seen some OC videos for my mobo, and although some are unclear on certain things, more often than not they point to LLC being a factor. Can you explain that a little? (Not sure if that should be another thread)
 

keith12

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I've a Wraith Max. It's a 125w CPU cooler. I think it's the one that comes with the 1700/1800. My PC is a custom build, and although I know the 1600x doesn't come with a cooler, the custom build didn't charge me for the Wraith Max.

Thanks for the info. When i first got the PC, I ran it for 24 hours on Prime95. No issues. Temps were about 72c max. That was at 1.375 Vcore. At 1.325 vcore and 24 hour test, the tamps maxed out at 67'ish or something. At 3.75ghz @1.325 vcore the temps were 70. I think there's a bit of room for more speed. edit: I didn't do more than 2 hours at these settings, but will for completeness

Not concerned about longevity in the CPU as such. Once I establish the best OC i can achieve and is rock solid, then I will save it as a profile, and revert to default. The 1600x at stock is great for my needs. I play BF1 at Ultra on 1080p @60hz at 80-100 fps and I'm happy out! But if i need to bump it a little in the future, then I already have the OC hooked in. That's my objective.
 

shrapnel_indie

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LLC, or Load Line Calibration, is used to combat Vdroop (as it tends to be labeled), which is where voltage drops a little as power demands go up. When set right it makes sure Vin (or Vcore in older cases, the way I understand it) is compensated to counter that voltage droop as closely as possible, to keep your CPU operating stably while overclocked. Too little, and your CPU could become unstable under heavy load. Too much and you run the risk of over-volting.

Here is some more reading on the subject:
https://linustechtips.com/main/topic/24019-load-line-calibration-why-overclockers-should-care/
https://www.msi.com/blog/why-llc-is-your-friend-when-overclocking
 

shrapnel_indie

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It will change with clock multiplier and power state where AMD, in this case, has decided it makes a difference. Within a given state and multiplier, it will not change. Change one or both of those, it will change. Other than those changes, it won't change. (change FSB, or motherboard/bus clock, it won't change. Change your selected voltage, it will not change.
 

TJ Hooker

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Why? My VID with my CPU at max clocks is 1.23V. I've never heard anyone suggest that's even close to the max safe voltage for Skylake.

Edit: Unless VID means something different for Intel vs AMD...
 

keith12

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okay, i get understand better now. Thanks.
 

keith12

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thanks for the links. That has helped some. I have noticed when at full load, the voltage dropping quite substantially. like going anywhere from 1.3/1.4 and sometimes dropiing as low as 1.265 (or something close to that) - so that is the vdroop? And changing LLC will help with that, and increase stability. I think there is 4 settings. I have left it on auto to this point. Settings are something like - Normal, High, Extreme and something else, I can't remember. So would a high setting(being in the middle) be the best for a moderate OC, or is it something I should try and judge myself?
 

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