Resizeable BAR support issues

Discussion in 'Videocards - AMD Radeon Drivers Section' started by Espionage724, Nov 26, 2020.

Tags:
  1. Astyanax

    Astyanax Ancient Guru

    Messages:
    10,116
    Likes Received:
    3,601
    GPU:
    GTX 1080ti
    SR-IOV = Multi VM Passthrough

    Nvidia has enabled single vm passthrough.
     
    BlindBison and nizzen like this.
  2. BlindBison

    BlindBison Master Guru

    Messages:
    570
    Likes Received:
    102
    GPU:
    RTX 2080 Super
    There are a couple features I really wish they would just add to the standard control panel — like, why is the only way to enable half refresh Vsync in the control panel the “adaptive” way which doesn’t work correctly with the low lag Vsync trick?

    Seems so silly since surely all it would take to change something like that is adding the option that already exists to the existing dropdown, yet they choose force users into grabbing inspector.

    I just don’t get it — like, some of these features are useful enough to be included in the standard panel I mean.

    In general I’d argue the whole control panel could use an overhaul as, in my own opinion at least, AMD’s control panel looks a lot better nowadays, but I suppose function is the most important thing.
     
  3. Chrysalis

    Chrysalis Member Guru

    Messages:
    186
    Likes Received:
    16
    GPU:
    RTX 3080 FE
    Asrock in the end were decent, they enabled all way back to z370, first bios was broken, they could have turned round and said sorry we wont support but got a fixed bios out a day later, also they communicated great on my ticket.

    Sadly the new bios seems to be broken on some other minor options now, like TPM cant be disabled anymore. But otherwise seems to be working fine.

    I expect the feature can go back several hardware generations but the vendors will want to encourage people to upgrade.
     
    BlindBison and Undying like this.
  4. aufkrawall2

    aufkrawall2 Master Guru

    Messages:
    771
    Likes Received:
    106
    GPU:
    6800 reference UV
    New bios 4.70 for X470 Taichi supports it too, but Above 4G Decoding still degrades CPU bound performance e.g. in RDR2. :(
    It doesn't do that for me with my B560 Pro4/11400F, though there CAM doesn't work at all yet and traps you in a stuck booting process...
     

  5. Fox2232

    Fox2232 Ancient Guru

    Messages:
    11,737
    Likes Received:
    3,327
    GPU:
    6900XT+AW@240Hz
    Same for other X470: Taichi Ultimate; Master SLI(/AC); Gaming K4; Gaming ITX/ac

    (For those who missed meaning of "Above 4G Decoding" which was available in all BIOSes. It is AGESA 1.2.0.0. So we can test.)
     
  6. Netherwind

    Netherwind Ancient Guru

    Messages:
    7,669
    Likes Received:
    1,535
    GPU:
    MSI 3080 Gaming X
    Tried this today but I noticed that my boot drives are gone when I enable 4G Decoding and Re-size BAR. CSM is disabled by default.
     
  7. Sylencer

    Sylencer Member Guru

    Messages:
    116
    Likes Received:
    31
    GPU:
    RTX 3090 Strix OC
    Drives are GPT format or MBR? Since MBR won't work.
     
    HD64G likes this.
  8. Fox2232

    Fox2232 Ancient Guru

    Messages:
    11,737
    Likes Received:
    3,327
    GPU:
    6900XT+AW@240Hz
    Gone from boot selection or gone from storage overview? Because when OS is installed with CSM ON, it may result in loss of bootability when it gets disabled.
     
  9. Espionage724

    Espionage724 Member Guru

    Messages:
    109
    Likes Received:
    45
    GPU:
    Radeon RX 580 8G
    Is it anything significant? Can it be reproduced in a notable manner (like 100-200+ points) with a CPU benchmark like GeekBench?
     
  10. aufkrawall2

    aufkrawall2 Master Guru

    Messages:
    771
    Likes Received:
    106
    GPU:
    6800 reference UV
    It is not something like a general loss of CPU performance across all applications. There are very specific issues with some games, drivers and probably even bioses.
    Though my impression is that in the best case, rBAR doesn't help CPU performance at all, as often is implied, but instead merely closes GPU utilization gaps (due to resource uploads?).
    The Above 4G Deociding issue in RDR2 is significant, yes. It's something like ~15% loss when CPU bound and CPU utilization is noticeably higher also when GPU bound vs. Above 4G Decoding off (if you're affected). Some scenes like the desert sunset of the benchmark seem to be affected especially bad, with figures like 60 vs. 90fps.
     

  11. Netherwind

    Netherwind Ancient Guru

    Messages:
    7,669
    Likes Received:
    1,535
    GPU:
    MSI 3080 Gaming X
    Well done, that's indeed the root cause. I'll have to reinstall Windows someday with my OS NVMe in GPT rather than MBR.

     
  12. lamiska

    lamiska New Member

    Messages:
    4
    Likes Received:
    9
    GPU:
    AMD RX5700
    Netherwind and HD64G like this.
  13. Netherwind

    Netherwind Ancient Guru

    Messages:
    7,669
    Likes Received:
    1,535
    GPU:
    MSI 3080 Gaming X

Share This Page