Dell XPS Speed Shift

Discussion in 'Dell XPS and Studio XPS' started by pressing, Oct 8, 2016.

  1. pressing

    pressing Notebook Deity

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    I'm not an expert but I have read that both EIST & SST can be activated simultaneously and the processor & O/S sort out the processes. But EIST is really laggy.

    Turbo requires SpeedStep and C3 (plus C6?) states to be enabled in BIOS. The work around I use is via ThrottleStop. In BIOS I have both SpeedStep and C-States enabled. Then in ThrottleStop, I disable laggy SpeedStep but top turbo speeds remain. In ThrottleStop I disable the very laggy C1E States. There I also enable SpeedShift. These settings are verified in HWiNFO64.

    EDIT - To be clear, real-time audio performance improved when I disabled C-States in BIOS. But that disabled the turbo and the processor maxed out at 2.2GHz. By enabling C-States in BIOS but killing laggy C1E states in ThrottleStop, I got the best of both worlds: turbo performance and removed the problematic C-States.

    I never found a way to disable SST without turning off the computer. That said, the large Intel PDF on the first post might give you some insight.

    For improved performance in real-time audio, I also noticed a difference turning off anti-virus software. Not via settings which didn't help. But in W10 pro going to Local Group Policy editor and "enabling" "turn off windows defender". I also tried removing Windows Defender for another lightweight antivirus program but that did not help. Use caution without internet!



    Thanks for the insightful summary arshcaria!
     
    Last edited: Dec 3, 2016
  2. GoNz0

    GoNz0 Notebook Prophet

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    Well we have been told enabling speedshift in throttle stop can be done but turning off can't so I expect this is a reboot to disable job.

    As for entries in the power plan I assume windows checks what is available during install and adds the features, maybe someone due to reinstall can confirm this.
     
  3. Techland

    Techland Notebook Consultant

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    That might be. But obviously then Dell still has a reason not to enable/add this feature, as the majority of existing customers do not get those controls.
     
  4. Techland

    Techland Notebook Consultant

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    pressing, thanks for the detailed explanation.

    Yeah, Windows Defender is a terrible performance brake. I configured its settings to not scan many things, including a lot of programs where it multiplies the start time (compressed exe) significantly. One day I might go back to Avira, where I never had these problems for the last 6 years.
     
  5. GoNz0

    GoNz0 Notebook Prophet

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    I disable defender by group policy or it is never totally turned off, it's worst than a bloody virus!
     
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  6. arshcaria

    arshcaria Notebook Enthusiast

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    I just did a performance test with different EPP values.
    The test is done via building an Android project using Android Studio and measuring the consumed time.
    Building Android projects involves reading/writing/compiling a huge amount of files so it can properly test the burst performance of different EPP values of speed shift.

    Code:
    EPP       0           128        192        224         255
    #1        4.614       5.04       7.697      11.615      13.657
    #2        4.518       5.69       7.842      11.641      13.932
    #3        4.366       5.006      7.679      12.067      13.735
    #4        4.27        5.025      7.859      11.899      13.6
    #5        4.239       4.915      7.708      11.92       14.023
    
    avg        4.442      5.190      7.769      11.806      13.731
    
    ratio      1          0.856      0.572      0.376       0.324
    
    Time unit: seconds
    
    Hope this can be a guideline of choosing desired EPP values with proper tradeoffs.
     
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  7. goodwin_c

    goodwin_c Notebook Enthusiast

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    As expected, between 0 and 128 there is no so much difference, but not bad battery saving. After 128 more aggressive power saving begins.
     
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  8. pressing

    pressing Notebook Deity

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    Arshcaria,

    That is an interesting set of statistics - thanks for taking the time to run them.

    Did you run them with both SpeedShift & SpeedStep enabled? You can see that in HWiNFO64. There were some interesting related questions on the ThrottleStop Guide thread (I think). For example:

    1. how do SpeedShift and SpeedStep interact? When SpeedShift runs, does SpeedStep get superseded, does it positively-neutrally-negatively impact performance?

    2. How do performance of SpeedShift vs disabling C-States compare?

    If you have some extra recreational time, maybe you could run a few quick independent scenarios testing:

    1. Try disabling SpeedStep by unchecking that box in ThrottleStop
    2. Try disabling C1E in ThrottleStop. Those C-States seem to cause a lot of performance issues
    3. Try fully disabling C-States in BIOS
     
  9. arshcaria

    arshcaria Notebook Enthusiast

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    Not sure how SpeedShift and SpeedStep interact, a pure guess is that SpeedStep is overridden when SpeedShift is enabled.

    In my test, setting SpeedShift EPP to 0 and disabling C-States give identical performance.

    1. Once you have enabled SpeedShift, disabling/enabling SpeedStep in ThrottleStop won't make any difference to the CPU frequency.
    2. Haven't tried that, maybe later I will.
    3. Haven't tried that, maybe later I will.
     
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  10. pressing

    pressing Notebook Deity

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    This is quite interesting! For my real-time music app you can see above that I had some differences.

    Let us know if you have the opportunity

    Thanks!
     
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