# Adrenalin 21.9.1 adds ReBAR support to Radeon 5000 series



## RPX100 (Sep 21, 2021)

Radeon™ Software Adrenalin 21.9.1 Release Notes


> AMD Smart Access Memory on Radeon™ RX 5000 Series Graphics



I am using Ryzen 7 3800 XT and AMD RX 5700 XT with Adrenalin 21.9.1 and was able to enable Smart Access Memory within Radeon Software.
*[BUG]: GPU-Z does still show that my GPU is not supported.*

_SAM can also be enabled without Radeon Software via Windows Registry:_
edit: HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Control\Class\{4d36e968-e325-11ce-bfc1-08002be10318}\0001
HKEY_LOCAL_MACHINE\SYSTEM\*CurrentControlSet*\Control\Class\{4d36e968-e325-11ce-bfc1-08002be10318}\0001
KMD_RebarControlMode REG_DWORD *1* (enabled) <- _this value will be "1" right after install (default setting)_


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## W1zzard (Sep 21, 2021)

Nice catch, what's the driver date and version shown on first tab?


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## RPX100 (Sep 21, 2021)

driver date: Sept 10, 2021


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## W1zzard (Sep 21, 2021)

Does the attached build show the correct status for GPU support and driver support?

If you have the time, please test BAR disabled manually, and older driver.


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## RPX100 (Sep 21, 2021)

*The new build seems to be working as it should.* Thanks for the update.

- Tested with 21.9.1 (which supports SAM) and GPU-Z 2.41.6 now shows this correctly
- Tested with 21.8.2 (which does not support SAM) and GPU-Z 2.41.6 now also shows the missing driver support.

cheers

_Not sure if this is important or not, just wanted to let you know:_
- driver 21.9.1 (reinstalled just now)
- switched resizeableBAR to *disabled* (in BIOS)
- switched above 4G memory to *disabled* (in BIOS)

attached screenshot shows that GPUz reports "above 4G Decode" as *enabled*
-> I double checked this setting inside my BIOS and it is *disabled *within BIOS

_Not sure if this is an GPU-Z issue. CPU-Z Mainboard/BIOS view attached._


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## W1zzard (Sep 21, 2021)

This is probably a BIOS bug. What's the highest memory address you see in Device Manager -> View -> Resources by Type -> Memory

This is mine, with Above 4G Decode disabled, note how the highest address used is FFFF FFFF (4 GB)


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## RPX100 (Sep 21, 2021)

Well, made a screenshot of device manager with 4G enabled/disabled.
_So is this indeed an BIOS issue?_

At least we know that GPU-Z seems to be working then. That is all I wanted. ^^


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## W1zzard (Sep 21, 2021)

RPX100 said:


> So is this indeed an BIOS issue?


Looks like it. There's that one PCI Bus at the end of your list, that's clearly above 4 GB. 

No idea why the BIOS puts it at that address, since you requested everything to be located below 4 GB.


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## Tanzmusikus (Sep 21, 2021)

RPX100 said:


> HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Control\Class\{4d36e968-e325-11ce-bfc1-08002be10318}\0001


Thanks for the info and @W1zzard for the new GPU-Z version! 

For my system I have this registry path:
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Control\Class\{4d36e968-e325-11ce-bfc1-08002be10318}\0000

But better would be:
HKEY_LOCAL_MACHINE\SYSTEM\*CurrentControlSet*\Control\Class\{4d36e968-e325-11ce-bfc1-08002be10318}\0000
or
HKEY_LOCAL_MACHINE\SYSTEM\*CurrentControlSet*\Control\Class\{4d36e968-e325-11ce-bfc1-08002be10318}\0001

Best regards


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## W1zzard (Sep 21, 2021)

Tanzmusikus said:


> registry path


The registry path varies between machines. You can find yours using GPU-Z -> Advanced Tab -> General -> Registry Path


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## RPX100 (Sep 21, 2021)

W1zzard said:


> The registry path varies between machines. You can find yours using GPU-Z -> Advanced Tab -> General -> Registry Path


This is good to know. Thanks for pointing that out. 

He was referring to "*ControlSet001*", which just is a copy _(I did not know that)._
So "*CurrentControlSet*" is indeed the correct path. But it is even better that GPU-Z points you to the correct path.


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## W1zzard (Sep 21, 2021)

RPX100 said:


> which just is a copy


Technically it is not a copy but a reference/shortcut to the currently active ControlSetxxx


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## RPX100 (Sep 21, 2021)

Seems like we have reached a point, where I do have to accept that I do know next to nothing about the registry. ^^
I usually am only using MSI Afterburner and MorePowerTool to change driver settings.

With the release of 21.9.1 I installed the Radeon Software for a short time and enabled/disabled SAM with that switch.
And then I used a registry scanner to see which value was changed.
This way I also learned that installing 21.9.1 enabled SAM by default (on supported hardware).
_edit: Disabling SAM changed the value to "2" and my guess is that "0" is default for unsupported hardware = hidden setting)_

---
Thanks for the info. Thanks for the new GPU-Z version. Glad it is working.


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## W1zzard (Sep 21, 2021)

RPX100 said:


> I do know next to nothing about the registry


You know more than most, and I think you're the first to discover this KMD_RebarControlMode key


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## Tanzmusikus (Sep 21, 2021)

W1zzard said:


> The registry path varies between machines.


... by *user* profile (local) *account*:

HKEY_LOCAL_MACHINE\SYSTEM\*ControlSet001*\Control\Class\{4d36e968-e325-11ce-bfc1-08002be10318}
HKEY_LOCAL_MACHINE\SYSTEM\*ControlSet002*\Control\Class\{4d36e968-e325-11ce-bfc1-08002be10318}
HKEY_LOCAL_MACHINE\SYSTEM\*ControlSet003*\Control\Class\{4d36e968-e325-11ce-bfc1-08002be10318}

(better use: HKEY_LOCAL_MACHINE\SYSTEM\*CurrentControlSet*\Control\Class\{4d36e968-e325-11ce-bfc1-08002be10318} for actual user instead)

... and by *number of GPU*s (incl. iGPU, vGPU):

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class\{4d36e968-e325-11ce-bfc1-08002be10318}\*0000*
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class\{4d36e968-e325-11ce-bfc1-08002be10318}\*0001*
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class\{4d36e968-e325-11ce-bfc1-08002be10318}\*0002*


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## RPX100 (Sep 21, 2021)

W1zzard said:


> You know more than most, and I think you're the first to discover this KMD_RebarControlMode key


KMD_RebarControlMode - *0* = unsupported _(and hidden: not visible within Radeon Software)_
KMD_RebarControlMode - *1* = enabled _(default)_
KMD_RebarControlMode - *2* = disabled _(by user)_

As I said: fresh install of *21.9.1* will set it to *1* and changing the switch to disabled will change it to *2*.
_Just found this because I never have the Radeon Software installed at all (since I prefer Afterburner + MPT)._


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## W1zzard (Sep 21, 2021)

Tanzmusikus said:


> ... and user profile?
> 
> HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class\{4d36e968-e325-11ce-bfc1-08002be10318}\*0000*
> HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class\{4d36e968-e325-11ce-bfc1-08002be10318}\*0001*
> ...


That number is incremented for each new graphics device that gets installed, not related to user profiles


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## Tanzmusikus (Sep 21, 2021)

Yes, of course.


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## 19941994ra (Sep 24, 2021)

Hello guys, support for resizable bar is not yet implemented between AMD 5000 and Intel right? 

I've got a 5600xt paired with an Intel 9400f on a Asus Prime B360 m-a motherboard.

Both BIOS firmware and gpu drivers are updated, Resizable BAR is enabled on BIOS. 

Thanks!


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## RPX100 (Sep 25, 2021)

@19941994ra please take a screenshot of:

Device Manager > Display Adapter > (right click) on your Graphics Card > Properties > Tab: "*Resources*"

_If you only see "Memory Range" there, then your reBAR is not working.
You need to see "Large Memory Range" x1 there._

*GPU-Z seems to be working fine here - I think this is BIOS related.*


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## Tanzmusikus (Sep 25, 2021)

@19941994ra 
Your Board does not official support rBAR alias S.A.M./C.A.M., or do you got a special UEFI version from ASUS.
I don't think so.


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## RPX100 (Sep 25, 2021)

Tanzmusikus said:


> Your Board does not official support rBAR





source: PRIME B360M-A | Product Support

But I am not sure* if this is working for this CPU / GPU combination.*
_The BIOS update in the picture is only for "Nvidia RTX 30 series support"_

But at least the reBAR option seems to be available in the BIOS settings.


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## Tanzmusikus (Sep 25, 2021)

Then maybe he forgot to flash the new UEFI version, the CMOS reset ... or the RX 5600 XT hasn't got compatible VBIOS?
If there are two VBIOS, then switch to the other and try again.

Important is what the AMD radeon driver shows in [Performance] -> [Configuration] -> "Smart Access Memory".




RPX100 said:


> The BIOS update in the picture is only for "Nvidia RTX 30 series support"


Okay, that should be the reason.


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## 19941994ra (Sep 26, 2021)

Thanks a lot for the replies, yeah it must be that is only enabled for rtx 3000 series as of now (guessing the "auto" only enables if it detects one of those). Fingers crossed ASUS adds support for RX cards too.

For further clarification:

- My GPU has the latest vbios update.
- BIOS shows the option enable rebar both in pci options and in a button top right of the main bios screen.
- No large memory in Windows device manager.
- No rebar option in Radeon software.


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## RPX100 (Sep 26, 2021)

19941994ra said:


> only enabled for rtx 3000 series as of now


Keep watching your BIOS update webpage... this entire reBAR support thing is still ongoing.
_New BIOS might be on its way within a few weeks - has been like that since Dez 2020. ^^_

Also double check in your BIOS if there is the option to "ENABLE" the setting (instead of "AUTO")
_"AUTO" setting might default to disabled on some boards/BIOS versions._


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## qualk (Oct 11, 2021)

RPX100 said:


> Device Manager > Display Adapter > (right click) on your Graphics Card > Properties > Tab: "*Resources*"
> 
> _If you only see "Memory Range" there, then your reBAR is not working.
> You need to see "Large Memory Range" x1 there._
> ...


I turned it on, and AMD Radeon Software shows that it's enabled, but there is no "Large Memory Range".


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## eidairaman1 (Oct 11, 2021)

There is a new driver out already


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## RPX100 (Oct 11, 2021)

qualk said:


> AMD Radeon Software shows that it's enabled


If Radeon Software lets you enable this feature, then it is indeed working just fine for you.

_You can double check with the latest GPU-Z (2.43.x) and looking at the "Advanced"-Tab,
and then select "PCIe Resizeable BAR" from the dropdown list._


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## qualk (Oct 11, 2021)

RPX100 said:


> If Radeon Software lets you enable this feature, then it is indeed working just fine for you.
> 
> _You can double check with the latest GPU-Z (2.43.x) and looking at the "Advanced"-Tab,
> and then select "PCIe Resizeable BAR" from the dropdown list._


That's the thing. GPU-Z shows it's disabled.


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## RPX100 (Oct 11, 2021)

Post screenshots of GPU-Z (1st Tab and Advanced PCIe) and maybe @W1zzard can see what is going on.
Show what *device manager resource view* is showing as well. Maybe we can figure out what is happening.

edit: this may be related to XFX or RX 5600 XT - continue in your thread, rather than this one here.


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