Resizeable BAR support issues

Hello,

My 2 cents.

My config :
- ROG STRIX X570-E Gaming with BIOS 3405 (AGESA V2 PI 1.2.0.0)
- Ryzen 2 : 3800XT
- Vega 64 LC
- Windows 10 20H2
- Adrenalin 21.2.2

Evidently, I only have a good motherboard but not the right graphic card nor the CPU.
I decided to test nonetheless, so I clicked in the "ReSize BAR" BIOS menu entry.
It is like in this screenshot from PhazDelta.

I then booted to Windows and like Espionage724, I have the entry "large memory range" appeared in the graphic card Windows properties window.
But in GPU-Z 2.65, only 256Mb on memory 3 and memory 7, like the OFF screenshot of reslore.

 

Any games testing you've done?

 

After MSI published the BIOS in December 2020 for Tomahawk B450 Max enabling the SAM feature, I thought I should test it even having a 2600X with an RX5700. And a few days ago I did so finding the results below:

Rome2TW SAM on: 175FPS maximum, 96FPS average, 65FPS minimum
Rome2TW SAM off: 149FPS maximum, 94FPS average, 64FPS minimum

DirtRally SAM on: 178FPS maximum, 150FPS average, 110FPS minimum
DirtRally SAM off: 175FPS maximum, 142FPS average, 89FPS minimum

Games as Ghost Recon Wildlands and the (vulkanised through the DXVK) AC Odyssey didn't show any performance differences.

Another change from enabling this feature is that the loading screeens when getting in the gameplay take significantly less time.

 

Not to be accusatory, but could I ask for a source please?

 

You can, but you'll need to sign an nda to read it.

 

Only Hitman 2 and Cyberpunk 2077, and I didn't notice any difference.

 

interesting article:
Radeon RX 5700XT, Radeon VII and RX Vega do not offer direct support for Resizeable-BAR, but it could be done | Backgrounds

https://www.igorslab.de/en/radeon-r...or-resizeable-bar-but-can-do-it-well-reasons/

 

There is nothing specific in the pcie device that is missing to do it.

 

just imagine the huge advantage of being bound to current upload heap limitation from NVME devices..



Throw away those limits are the start point for getting any advantage from direct storage.

 

Quick test with my X470 Gaming Plus MAX which got new BIOS yestarday with my Ryzen 5 3600 + RX 5700:

RDR2 with REBAR ON:

Avarage FPS: 28.7
Min FPS: 25.1
Max FPS: 34.6


RDR2 with REBAR OFF:

Avarage FPS: 28.2
Min FPS: 12.3
Max FPS: 36.1

I have also tried Dirt Rally and Forza Horizon 4, however results there were same for rebar on/off. I have rebooted between each try and have done several same benchmarks to make sure numbers are not fluctuating too much.

 

ResizeBAR Enabled status on GPU-z with Ryzen5 1600(AE) + RX VEGA56 (adrenalin 21.2.3)

 

Resizeable BAR showing enabled on my Fury.... Not that it'll be of any use of course, hopefully, next week it'll be enabled for a different GPU altogether....

 

How the hell a 5600 XT won't have it enabled but a Fury does?

Damn it, AMD.

 

Is resizeable BAR enabled on my RX 480 ?

 

intel 10/11gen or amd zen2/3 cpus and nvidia rtx3000 or amd rx6000 gpus only. Depending on your board and bios you can enable resize bar even on older hardware but i dont think its any beneficial.

 

Positive!

 

Yes, I know that.
I am on a ROG Strix B550-F and a 5800X.
But, what I mean is that, not even have it "Enabled" on GPUZ unlike other people with older cards. Obviously, I have ReBar ON in the BIOS.

 

I'm getting a dxgkrnl.sys BSOD every time I enable Resizeable BAR, x470 Crosshair VII Hero (Wi-Fi), Ryzen 3600, AGESA 1.2.0.0 (4204 bios), 5700 XT Red Devil, Win 10 20H2.867. It happens randomly, even firefox can cause it. )))

 

I didn't enabled it recently, but when I was doing some tests last time, even with my X570 motherboard and the BIOS with AGESA 1.2.0.0, I had random BSOD as well. :-(

Thus, I disabled it and will test when I'll flash with AGESA 1.2.0.1 but with a 3800X and a Vega64, I have absolutely no hope it would bring any improvement whatsoever (not that I complain, my Vega64LC's performances don't bother me in 1440p).

 

People are already analyzing the changes to z390 bios's to see if support for rebar can be ported back to x99 and 79