PCIE x16 vs x8 still a thing?

Discussion in 'Video Cards' started by dvsman, Sep 28, 2018.

  1. dvsman

    dvsman 2[H]4U

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    So I'm thinking of consolidating some rigs at my place just to simplify things a bit.

    Right now I'm debating on either keeping my
    1) x99 5930k system with SLI 2x Titan Xp (x16+x16) or
    2) maybe swapping in parts from my x470 HTPC 2700x + SLI 2x Titan Xp (x8+x8)

    Older with more PCIE lanes or newer with less PCIE lanes?

    EDIT: Use case is all around home PC - so mostly effing around the internet / games / photgraphy related and occasional transcoding video.
     
    Last edited: Sep 28, 2018
  2. Araxie

    Araxie [H]ardness Supreme

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    I would say older with more PCI-E lanes.. yes, there's a difference which may be considerable in some games of up to 10FPS even in single card configuration, but is not only about RAW FPS consistency and averages, game smoothness suffer a lot in those bandwidth constraint scenarios and with SLI this is one of the more important things to take in consideration, keep games fluid and smooth are already a challenge in SLI to add bandwidth limitations.. again, from 0 to up to 10FPS may not be noticeable for everyone so, you may just want to test several games in each platform on the games you play to see if there are a noticeable issue for you.
     
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  3. defaultluser

    defaultluser I B Smart

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    Yeah, unfortunately the only place I know that does consistent bandwidth tests on new cards is TechPowerUp,an hey only test averages.

    There are significant hits on some new games (even recording average FPS only), but it's probably a lot worse than they've been able to report.

    https://www.techpowerup.com/reviews/NVIDIA/GeForce_RTX_2080_Ti_PCI-Express_Scaling/

    I usually double the average percent performance hit as a rough guess at min/max. So if you're seeing a 10% average performance drop at 8x, then it's probably peak of +/- 20%.

    We've had PCIe 3.0 since 2011, and it's at the end of it's life in the 8x configuration. I wouldnt buid a new system intended to run high-ed cards at 8x8 until we have PCIe 4.0 motherboards.

    New games like Assassin's Creed Origins ,Hellblade, Wolfenstein 2 report average performance drop of 10% or more at 1080p.
     
    Last edited: Sep 28, 2018
  4. dvsman

    dvsman 2[H]4U

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    Thanks guys - that's kinda good news for me. I didn't really want to have to rip two different PCs apart to cobble them into one PC. A swap of video cards is much much easier to deal with!
     
  5. crazycrave

    crazycrave Limp Gawd

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    I have 2 different Ryzen test rigs with one having a 2200G (x8) and 1600 (x16) .. the 2200G has faster 3200Mhz memory and overclocked to 3.9Ghz it can only make the 290x have what you see as gpu score here .

    https://www.3dmark.com/compare/fs/16596948/fs/16378928#

    Where as the 1600 running stock clocked and 2133Mhz Memory makes the 290x have a 200+ point gpu score , so it does show that it limits it being x8 PCI Express as clocks for video card never touched, so I would agree about 5-10% different in performance between them.

    https://www.3dmark.com/fs/16474020
     
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  6. Gamer237

    Gamer237 [H]Lite

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    for this generation no, however for the new RTX cards going 8x from 16x has a small impact. with your setup you should be fine
     
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