How to make Link speed 2.5GT/s to 5.0GT/s on ATI card and Nvidia card

Discussion in 'Mac Pro' started by fouel, Feb 22, 2013.

  1. itdk92 macrumors 6502

    itdk92

    Joined:
    Nov 14, 2016
    Location:
    Copenhagen, Denmark
    #226
    Can’t download OceanWave anywhere, and the new Compubench crashes on the ocean scene ( running on the 10.13.4 beta)

    Do you have it? :)
     
  2. h9826790, Mar 18, 2018
    Last edited: Mar 18, 2018

    h9826790 macrumors G5

    h9826790

    Joined:
    Apr 3, 2014
    Location:
    Hong Kong
    #227
    This new apps can also test the bandwidth. It's from Apple Appstore and free. Safe to use.

    https://itunes.apple.com/hk/app/cl-ing/id1244392031?l=en&mt=12

    1) Open the apps
    2) Go to Performance tab
    3) Select your GPU at the bottom (choose OCL option)
    4) Run one of the Compute test (e.g. Single Precision Scalar)
    5) Observe the Memory bandwidth test result

    If it's 5GT/s, the number should be around ~5000MB/s (as per the following screen capture)
    Screen Shot 2018-03-18 at 23.19.00.jpg
     
  3. krakman macrumors regular

    Joined:
    Dec 3, 2009
    #228
    I dont think this software reports correctly.....
     

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  4. h9826790 macrumors G5

    h9826790

    Joined:
    Apr 3, 2014
    Location:
    Hong Kong
    #229
    Why?

    Without running benchmarks, the bandwidth will stay at ~2500MB/s. That's normal, because the negotiation speed is dynamic. But once start to stress the card, the number will jump to ~5000MB/s. That looks perfectly correct to me.
     
  5. Raunien macrumors 6502

    Joined:
    Aug 3, 2011
    #230
    How much of a difference is it if my Rx 580 runs at 2.5 GT/s vs 5 GT/s? Is there any way for a Rx 580 to run at 5 GT/s?
     
  6. krakman macrumors regular

    Joined:
    Dec 3, 2009
    #231
    Sorry my mistake I was looking at "device to device" speed
     
  7. rawweb macrumors 6502a

    rawweb

    Joined:
    Aug 7, 2015
    #232
    I wish the apple kext for the AMD side would perform whatever voodoo the NVIDIA web driver does to switch on 5 GT/s

    Screen Shot 2018-03-18 at 8.52.26 PM.png
     
  8. itdk92 macrumors 6502

    itdk92

    Joined:
    Nov 14, 2016
    Location:
    Copenhagen, Denmark
    #233
    Yes. I confirm that VEGA seems to run at pcie 1, too
     
  9. failcl macrumors newbie

    Joined:
    Apr 7, 2018
    Location:
    Hong Kong
    #234
    HELLO

    My Name is Sam , I have Sapphire R9 280X Display Card

    I Flashed the rom !!! Now have mac boot screen, But only have pci-e 1.1 speed (2.5 GT/s)
    I know need to remove the r17 !!! but i don't how to remove it !!!
    Who can help me !!!
    Many Thanks !!!
     

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  10. The Spirit macrumors member

    The Spirit

    Joined:
    Jun 23, 2010
    Location:
    Germany
    #235
    Hi.
    Is there also a resistor mode available for the HD7870?
     
  11. RetroDan macrumors member

    RetroDan

    Joined:
    Dec 17, 2015
    Location:
    Michigan
    #236
    I'm still waiting for the RX 580 Resistor mod...
     
  12. RetroDan macrumors member

    RetroDan

    Joined:
    Dec 17, 2015
    Location:
    Michigan
    #237
    Strange to think that the resistor mod is now completely unnecessary, thanks to the official Apple firmware update. 138.0.0.0.0 fully enables 5GT/s speed for the RX 580. Best thing Apple has done in years.
     

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