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How to find out if SAM / Resizable BAR is enabled in windows

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I was looking to see how I can tell if BAR is enabled in windows besides running benchmarks and compare. Well someone figured it out.

After you enable it in the BIOS, boot into windows and follow these steps.

  1. Go to Device Manager
  2. Under display adapters - right click on your GPU
  3. Click properties
  4. Go to the resources tab and make sure that "Large Memory Range" is listed.

SAM.jpg

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On my system I go to Advanced\PCI Subsystem Settings, and Enable Above 4G Decoding, than the Re-Size BAR Support option appears with option to run in Auto or Disabled.

Than go to Boot section and confirm CSM is Disabled, and everything is good to go.

 

Edited by Braegnok

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On the MSI Z490 Unify,  after updating the BIOS its either Disabled (default) or enable. I'll take a screenshot when I am home. Haven't tried it on the ASUS X570 Hero yet. I have to reinstall windows since CMS must be disabled. I'm running off a SATA drive so it fails to boot when disabled. apparently a windows reinstall with it disabled is the only fix.

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I might need to update PCI drivers or install an update from Nvidia, after enabling Re-Size Bar Support in BIOS, Bar support is not showing in Windows when I checked. 

1769157132_MemoryRange.thumb.jpg.d536659f7fda7c02c4ba855a03ceeef3.jpg

Edited by Braegnok

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I just finished testing AC Valhalla. This is a unbelievable amount of increase. Now I must do some more A/B testing on other cards and games to see if they are affected as well. I am 99% sure these are accurate. I did these test back to back with multiple runs. Just hard to believe

So far NVIDIA has not said anything supporting this feature. At least not in any currently card out. If they do...well I will have a lot of retesting to do.

 

6800XT AC Valhalla BAR Testing:

1920x1080 BAR Disabled: 121 FPS

1920x1080 BAR Enabled: 140 FPS

2560x1440 BAR Disabled: 97 FPS

2560x1440 BAR Enabled: 110 FPS

 

MSI UNIFY Z490 BIOS

MSI_SnapShot_02.jpg

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Vary nice performance boost! 

Well that explains why I can not see anything in Windows with the 3090, dang it!  :no:

looks like your going to be doing a lot of retesting in a few months, most boards will support Re-Size BAR with RTX 30 series cards after Nvidia releases VBIOS update in March. https://www.nvidia.com/en-us/geforce/news/geforce-rtx-30-series-resizable-bar-support/#:~:text=New GeForce RTX graphics cards,graphics cards starting in March.

Edited by Braegnok

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Looks like AGESA COMBO PI V2 1.2.0.0 for AMD now support NIVIDA GPUs resizeBAR. I'm not sure if NIVIDIA needs enabled it in the drivers. I suspect so.

 Using the past AGESA 1.0.9 for the X570 does not work with NVIDIA BAR support even though it does for RX,6800-6900 cards. 

Having issues getting any memory above 3600 to boot. Time to play with the voltages again....

Edit: Figured it out after only 3 Hours! (insert sarcasm) It looks like the newest AGESA requires a bump in memory voltage. What was once bootable at 1.4v, now takes 1.45 and to get it to pass Memtest86 it is now 1.5v. No wonder so many people are reporting their previously working memory is no longer booting. AMD did something that messed with the memory....

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I use a steel legend b450m when I am going to enable the resizeble bar he asks me to disable the CMS, I do this, I enable the resizeble bar but when I save the settings and restart it goes back to the bios, what can it be? After enabling the resizeble bar do I enable the CMS too?

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hi, can you help me? I use a steel legend b450m when I am going to enable the resizeble bar he asks me to disable the CMS, I do this, I enable the resizeble bar but when I save the settings and restart it goes back to the bios, what can it be? After enabling the resizeble bar do I enable the CMS too?

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I think the problem you are having is windows was installed with CMS enabled instead of the now standard  UEFI mode. The simple solution is to reinstall windows with UEFI enabled instead of CMS, but I'm sure someone on the internet has a better way.

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Nvidia Control Panel, System Information, Display: will also confirm Resizable BAR working.

RBAR.thumb.jpg.5678d767220de9e404f4a7a653e7a175.jpg

 

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