# GPU-Z numeric PerfCap reasons?



## dononelson (Apr 4, 2016)

Hi all, newbie to this forum here.  I recently started using gpu-z, and decided to log the results to a file.  After importing the log into Excel, I found that the PerfCap reasons were numeric.  Can anyone translate what reason "0" (zero) is?  I know that 16 is probably "Util", but during a session of Crysis 3, it changed to zero.  During that time, GPU load was 99%.

Any help is much appreciated.


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## W1zzard (Apr 4, 2016)

```
/*!
     * Power. Indicating perf is limited by total power limit.
     */
    NV_GPU_PERF_POLICY_ID_SW_POWER = 1,
    /*!
     * Thermal. Indicating perf is limited by temperature limit.
     */
    NV_GPU_PERF_POLICY_ID_SW_THERMAL = 2,
    /*!
     * Reliability. Indicating perf is limited by reliability voltage.
     */
    NV_GPU_PERF_POLICY_ID_SW_RELIABILITY = 4,
    /*!
     * Operating. Indicating perf is limited by max operating voltage.
     */
    NV_GPU_PERF_POLICY_ID_SW_OPERATING = 8,
    /*!
     * Utilization. Indicating perf is limited by GPU utilization.
     */
    NV_GPU_PERF_POLICY_ID_SW_UTILIZATION = 16,
    /*!
     * SLI GPUBoost Synchronization.
     */
    NV_GPU_PERF_POLICY_ID_SW_SLI_GPU_BOOST_SYNC = 32,
```

The value can be a combination of two or more flags, in which case they get added (technically OR'd). E.g.: 18 would be SW_THERMAL + SW_UTILIZATION (2 + 16)


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## dononelson (Apr 4, 2016)

hmmm, then I wonder what zero is?  This is a GEForce 660M. Here is a snippet of the log:


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## W1zzard (Apr 4, 2016)

Zero means no perfcap active


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## dononelson (Apr 4, 2016)

That's interesting - when the card is idle, it has a PerfCap of 16 (Utilization), but when GPU load is 99%, it has no PerfCap active...


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## FYFI13 (Apr 4, 2016)

dononelson said:


> when the card is idle, it has a PerfCap of 16 (Utilization)


Performance is limited (capped) due to very low utilization (load).


dononelson said:


> when GPU load is 99%, it has no PerfCap active...


The card is working on full power, hence it's performance is not capped. Also it means that card is not overheating, no being over-volted and so on.


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