Dell XPS Speed Shift

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

  1. GoNz0

    GoNz0 Notebook Prophet

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    Thanks for this but I think it should be down to the user to decide if they want to risk bricking a laptop and should only be done if you have a valid warranty so Dell can come swap the mobo! :)

    A link to the guide would also help.
     
    Last edited: Nov 28, 2016
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  2. goodwin_c

    goodwin_c Notebook Enthusiast

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    That's why i decided to post it there. People have right to decide. Just want to filter newbies that will break laptops and than will start crying everywhere. About guide - just forgot to insert link. On evening will find it again and edit my post.
     
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  3. pressing

    pressing Notebook Deity

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    Blurblur,

    As you probably know, there are over a dozen undervolt results posted here at NBR and one user posted a spreadsheet summarizing some of those results. Each chip is different so you need to stress-test your system to know where your CPU stands but user reported data provides a good baseline. The i5 has a lot of undervolting potential (vs i7).

    I run -170mv on the CPU-cache and it provides massive thermal benefits with zero instability. You might try testing a more aggressive undervolt. Interestingly, the related new Kaby Lake chips take advantage of this delta, and the "increased performance" corresponds to very little undervolt head-room.

    Also, you should run throttlestop on power plan "high performance". But on battery you might test running power plan "balanced" without throttlestop. Unrelated (I think), in Dell Command-power manager, under thermal settings "Quiet" probably provides better battery life than "ultra performance" does.
     
  4. arshcaria

    arshcaria Notebook Enthusiast

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    It seems that enabling SpeedShift overrides Windows built-in "High Performance" power plan CPU governing.

    Using windows "High Performance" power plan, without SpeedShift, the CPU is fixed at the highest frequency. With SpeedShift enabled, the CPU freq is no long fixed and jumps quickly. And this causes performance degrade. I ran geekbench W/ SpeedShift and the results were:

    Without SpeedShift
    Single-Core: 4293
    Multi-Core: 13042

    With SpeedShift
    Single-Core: 4167
    Multi-Core: 12812

    Of course, when using "Balanced" or "Power Saver", enabling SpeedShift will give better performance, because SpeedShift is faster in increasing the frequency.
    But is it possible to automatically disable SpeedShift when switching to "High Performance" power plan?
     
    Last edited: Nov 29, 2016
  5. GoNz0

    GoNz0 Notebook Prophet

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    it is probably due to a missing setting or windows performance being able to communicate properly with the BIOS, unless the dell xps13 users with proper speedshift support can confirm the same?
     
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  6. pressing

    pressing Notebook Deity

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    Those geekbench results are pretty close. Are the differences repeatable?

    With SpeedShift, in the ThrottleStop "Turbo Power Limits" window, did you set EPP=0 and max to your processor's max MHz (i5=32)?

    I'm still trying to figure how to enable absolutely highest performance, regardless of heat (as my music software program needs real-time, glitch-free processing of large amounts of data and does not have heat issues). What works for me now is basically:

    - Disable SpeedStep in BIOS
    - Disable C-States in BIOS
    - Use Windows "High Performance" power plan
    - Use Dell Command-Power Manager with thermal management at "Ultra Performance"
    - Use SpeedShift with EPP=0 & undervolt via ThrottleStop

    Under that scenario, the gitches disappear (well with networking disabled). However, the i5 doesn't seem to ramp up to full 3.2 GHz, rather peaking around 2.6GHz. Without SpeedShift, it seems to peak at 2.2GHz. Still trying to fine tune to get this running flat out at 3.0GHz +

    Some people argue that the processor should be running CONSISTENTLY fast so things like SpeedShift should all be disabled...


    This makes sense

    The new 9360 XPS13 does not have proper SpeedShift support either : (
     
  7. googlevich

    googlevich Notebook Enthusiast

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    Could you please provide a link to the guide. Thanks.
     
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  8. arshcaria

    arshcaria Notebook Enthusiast

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    Thanks uncelwebb.

    May I ask one thing? In ThrottleStop, can we apply different EPP values (in TPL) for different ThrottleStop profiles(Performance, Game, Internet and Batter)? For instance I would like to set EPP to 0 in Performance and Game profile and 255 in Battery profile. I found that single EPP value is applied to all profiles? You know I mean ThrottleStop profiles, not Windows power plans.
     
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  9. unclewebb

    unclewebb ThrottleStop Author

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    That is correct. Speed Shift allows the CPU to manage itself so the Windows power profiles become obsolete when it comes to managing the CPU speed.

    A different EPP value for each ThrottleStop profile is an excellent idea. Unfortunately, no time at the moment to add this feature. Maybe someday.
     
    Last edited: Nov 30, 2016
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  10. goodwin_c

    goodwin_c Notebook Enthusiast

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    Can't find that guide again, so i will describe it in short:
    1) format flash drive with FAT32 filesystem
    2) download that archive https://www.firewolf.science/wp-content/uploads/2015/04/EFI-shell.zip
    3) put efi file from archive into Boot/bootx64.efi on your flash drive
    4) boot from flash drive. you will get uefi shell
    If it is not booting - go to bios, boot sequence - and add custom entry pointing to that efi file. than reboot, F12 and choose your custom entry
    After that in shell
    Code:
    setup_var 0xD8
    
    It should return value 0x0. Next modify value:
    Code:
    setup_var 0xD8 0x1
    
    After reboot windows will be happy to enable Speed Shift for you. No more need to enable it manually from Throttle Stop (even who knows if it is working properly if you are enabling it after system boot)
     
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