# Can someone explain PerfCap for me?



## callannn (May 24, 2013)

Hi, first time poster so please bear with me. My laptop has a GTX 675M and after updating my drivers to 320.18 I checked out GPU-Z and noticed that in sensors some new details appeared, including PerfCap reason. Under this it is coming up as Util, which according to the info means that it is 'Limited by GPU Utilization'. Can someone please explain to me exactly what this means and, if possible, how to prevent any performance capping?

Cheers


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## Naki (May 25, 2013)

What laptop do you have? What Windows OS does it run?


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## W1zzard (May 25, 2013)

This is a feature of newer NVIDIA drivers. They report back why performance is capped (reason for clocks reduced)

When you are not running a 3D app, clocks go down -> Limited by GPU Utilization

Other possible values are when the card is running into power limit, or when it's running too hot. There are also cap reasons related to voltage.

This feature is experimental, I'm not sure how useful it is for users. Also due to a bug the graph will overflow to the left, drawing over current value and the label.


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## callannn (May 25, 2013)

Naki said:


> What laptop do you have? What Windows OS does it run?


I have a Samsung NPC700G7C running windows 7



W1zzard said:


> This is a feature of newer NVIDIA drivers. They report back why performance is capped (reason for clocks reduced)
> 
> When you are not running a 3D app, clocks go down -> Limited by GPU Utilization
> 
> ...


Ah right, so in that case will it always come under 'Util' when idle, but when playing a game or something like that it shouldn't list anything under PerfCap reason?

My card never gets too hot, nor does it run into power limit, and when viewing it i've never experienced that bug, but I have seen it mentioned so i'll definitely look out for it.


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## Darkh4 (May 31, 2013)

I was wondering about this myself.  I noticed PerfCap after upgrading to a 660 ti and running GPU-Z just to make sure everything looked stable.  

Whenever I'm running games, I get both vRel and vOp as messages, which are described as Reliability Voltage and Operational Voltage.  It goes back to Util after the game is stopped. 

What does this mean, exactly?  Is my card having trouble drawing enough power or getting stable power?  Should I be worried about my PSU?  It's a 3-year-old 850 watt Corsair, and it seems unlikely that it would be failing already. 

I should also note that I'm running this card at stock speed.  No overclocking.


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## W1zzard (May 31, 2013)

Darkh4 said:


> I get both vRel and vOp as messages, which are described as Reliability Voltage and Operational Voltage



unfortunately that's all i know. it certainly does not indicate any defect with your card.

boost automagically adjusts clocks and voltages, but obviously neither to infinity, so maybe it means that the card is at some voltage limit, which the boost algorithm can not pass for safety reasons.


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## Darkh4 (May 31, 2013)

W1zzard said:


> unfortunately that's all i know. it certainly does not indicate any defect with your card.
> 
> boost automagically adjusts clocks and voltages, but obviously neither to infinity, so maybe it means that the card is at some voltage limit, which the boost algorithm can not pass for safety reasons.



Ah, so it might just be my card hitting a voltage safety limit, and GPU-Z showing it as those errors.  I will keep an eye on it, but it makes sense. Thanks!


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## W1zzard (May 31, 2013)

Darkh4 said:


> Ah, so it might just be my card hitting a voltage safety limit, and GPU-Z showing it as those errors.  I will keep an eye on it, but it makes sense. Thanks!



that's my best guess.

what made you think it's reported as "error", and how should i change it so that it feels more like "information" ?


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## Maban (May 31, 2013)

Why don't I ever see any of these PerfCap things?


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## Darkh4 (May 31, 2013)

W1zzard said:


> that's my best guess.
> 
> what made you think it's reported as "error", and how should i change it so that it feels more like "information" ?



Well, partly the fact that one of the conditions shows up as an orange bar (orange usually means warning), and the fact that they only show up when the GPU is under heavy load.

GPU Utilization capping seems like the "normal" condition.  It's what you see when the GPU is at idle, and indicates it simply isn't being pushed to its limit.  While the others, especially the one about Voltage Reliability, sound like a fault state.  Like the voltage supply is not reliable. 

Something like "Voltage Limit" or "Voltage Throttling" might sound more like a controlled procedure, and less like an error.


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## Hilux SSRG (May 31, 2013)

Adding to the OP question, has anyone else observed any overclocking caps on 600 series cards after updating drivers to 320.18.  I assume gpu boost 2.0 is exclusive to 700 series for now?


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## Naki (Jun 1, 2013)

Maban said:


> Why don't I ever see any of these PerfCap things?


Do you have a Nvidia GeForce videocard? What model? What OS?
I believe you need a GeForce 6xx/7xx series videocard to see this.
EDIT: Hmm, you do have a GTX 680 card. No idea then. What drivers do you use? Let's wait for a comment from W1zzard.


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## Naki (Jun 4, 2013)

W1zzard said:


> that's my best guess.
> 
> what made you think it's reported as "error", and how should i change it so that it feels more like "information" ?



Change color from orange to some other (non-yellow and non-red ) color maybe?


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