Performance for Free: Unlocking Resizable Bar for unsupported AMD GPUs (Polaris, VEGA, Radeon VII)

I think i read somewhere you need to have catalyst installed (adrenalin)

 

Hi,

I found this forum from a YouTube video...

My system is: CPU: Ryzen 5 1600X, GPU: Gigabyte 5600XT Gaming OC 6Gb, MB: Gigabyte X470 Aorus Ultra Gaming.
I've updated the MB BIOS to the latest F64a version, disabled CSM, enabled 4G decoding, however there is no ReBAR option. I did DDU on the previous AMD GPU drivers and performed a fresh install of the latest drivers. Of course I enabled REBAR Legacy On.reg, restarted, however nothing changes...

 

says here you need a AMD 500 Series Motherboard

https://www.amd.com/en/technologies/smart-access-memory

 

this isn't true


gigabyte motherboards don't support SAM / rebar on Zen1 / Zen+ because of an artificial limitation. you can use rebaruefi on them to fix this. other AM4 motherboards don't have this issue and show SAM/rebar with any cpu (if they got bios update for it)

 

do you have the option to enable it in the Adrenalin software ?

 

Great thread! Just wanted to share my experiences with SAM/ReBar.

Asrock z77 Extreme4 (Bios mod)
i5 2500K @ 4.7GHz (Sandy Bridge/PCIE 2.0)
32GB DDR3 2133MHz
RX580 8GB (Bios mod/MagicGOP)
Win11 AME

Had to mod the motherboard bios of course but it was super easy thanks to win-raid and some very clever members. Noticeable performance increase (when measured, I can't see milliseconds of course) in all titles I've encountered including 3DMark, DX:MD, Hogwart's Legacy, FC6, AC:Valhalla, yadda yadda. Haven't found any titles yet that saw a drop in performance but I'm sure they're out there.
Embarked on this path late last year and there was concern that it might not work on such old hardware that is limited to PCIE 2.0 but here we are!
I lost access to an old stock pile of bench results but I grabbed a few screens today from AC:Valhalla that demonstrates the uplift even though Valhalla is a known hyper-responder to the ReBar treatment.
Anyways, highly encourage anyone thinking about undergoing the process and can highly recommend it.

TLDR;
20% uplift on Lowest 0.1%
16.3% uplift on Lowest 1%
30% uplift on Min FPS
6.7% uplift on Avg FPS
Max FPS..doesn't matter in this test cause it bounces all over run to run and is technically counting from before the scene has actually started so can't be relied upon.

 

I did not find my MB on the list of supported MB's and I was reluctant to try it. If I would do it, what guide should I use? Is it this one? https://github.com/xCuri0/ReBarUEFI/wiki/Using-UEFIPatch

 

I use vega 64 and it doesnt seem to work for me whatever i try in amd software its still disabled.

 

How do I make it work on a 4gb card?

 

Hi, 4GB cards are a hit or miss.

 

If the Option in Control Center is still greyed Out after you used the reg File, try changing

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Control\Class\{4d36e968-e325-11ce-bfc1-08002be10318}\0000

to

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

Did the trick for me with x470 mobo and a x580 8 gb

 

Quick question,
As I've read in this thread i can't enable SAM on my system: Ryzne 5 1600 AF, Aurus B450 Elite and RX 6700 xt (or can i and I'm just stoopid?), because my CPU is not supported even with the mod.

Next year I'll want to upgrade my CPU to a Ryzen 5 5000 series. Will it work then by default( I can't find anything about the aurus b450 supporting sam) or will i need to upgrade my mobo as well? If I also need to upgrade the mobo I'll be better of just going the full length and upgrading to the latest 7000 series CPU and 600 series mobo.

Thanks!

 

You probably need to update BIOS for your Mobo.

 

The mobo has the latest version installed(F65a with agesa v2 1.2.0.8) . I've also disabled CSM Support and i activated above 4g decoding but it seems that i don't have a re-size bar option to activate/deactivate or at least i cant find it.

 

Older Ryzen Processors like Zen and Zen+, you need to mod the BIOS in order to get ReBAR state working. Your problem is exactly like what I encountered before with my 3400G

 

Hey, so I have a AMD Radeon Vega 56 Pulse 8GB, an Intel i7-8700 and a ASRock B365M Pro4-F. In 2022 up til March or April the registry hack worked really well and it showed ReBar as activated in AIDA64 and GPU-Z. Now with the latest drivers, it does not work anymore. I don't understand why since I even tried to "hack" it again by applying the registry again. I also tried to install the NimeZ drivers everyone is talking about which apparently activates ReBar aswell, but it did not. Can someone explain it to me why this is not working anymore. My mainboard supports ReBar aswell as my CPU.
Cheers

 

If GPU-Z shows disabled your problem is BIOS

 

I dont think you understand. It worked earlier, with previous drivers, but now it does not. GPU-Z says "ReBar activated in BIOS -> Yes", so it has to do something with the new drivers and I dont want to roll back to older drivers.

 

Hey, nevermind, somehow it works now flawlessly, seen here in these pictures: