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[HOW TO] OpenCore 0.7.4 > 0.7.5 differences

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Monthly message by vit9696, please read it carefully, there is no better place to see what's new in OpenCore.
https://dortania.github.io/hackintosh/updates/2021/11/01/acidanthera-november.html

Main changes applied in 0.7.5 version:
  • Improved Linux boot and revised OpenLinuxBoot documentation
  • Fixed external drive icons
  • Updated builtin firmware versions for SMBIOS
  • Updated recovery downloading commands to include Big Sur and Monterey
  • Added support for GPU Resize BAR (RBAR).

config.plist
  • Booter >> Quirks >> ResizeAppleGpuBars (integer) whose default value is -1 (disables this quirk); reduces GPU PCI BAR size to be compatible with macOS.
  • UEFI >> Quirks >> ResizeGpuBars (integer) whose default value is -1 (disables this quirk); configure the GPU PCI BAR size for systems other than macOS; leaving it at -1 prevents this value from being applied by OpenCore to Windows or Linux.
Kexts
  • AppleALC 1.6.6 (new layouts added)
  • BrcmPatchRAM 2.6.1 (Improved BlueToolFixup compatibility with macOS 12) *
  • HibernationFixup 1.4.5 (improved behaviour when battery level is critical)
  • Lilu 1.5.7 (improved support for all 64-bit macOS versions)
  • VoodooPS2 2.2.7 (fixes)
  • VoodooRMI 1.3.5 (fixes, added new devices)
  • WhateverGreen 1.5.5 (improved backlight control in AMD RX 5000 series, fixed black screen in Skylake and newer).
* Monterey has brought major problems for third-party (non-native Apple) wifi and bluetooth devices. Developers are working hard to fix these problems. Little by little improvements are being made but we are still not 100%.

Notes about Resizable BAR (base address register)

Resizable BAR (RBAR) is a technology included in the PCI Express 3.0 specification since 2008 but until now it has been very little used. In AMD it is called Smart Access Memory (SAM). Its purpose is to increase the amount of VRAM (graphics card memory) that is accessible by the CPU. The limit has been kept at 256MB of VRAM memory for backward compatibility.

What RBAR does is allow the CPU to access all of the VRAM memory. The only restriction is imposed by the GPU itself. In theory the CPU can access all the VRAM but in practice the GPU always has the priority of use.
Its main advantage is in graphically demanding games. In this type of game, the CPU collaborates with the GPU performing the necessary calculation tasks for the execution of the game. Without RBAR, the CPU can only load 256MB into VRAM and the rest has to be loaded into RAM, which slows down the GPU from reading the data. With RBAR, all or most of the computational tasks performed by the CPU are stored in the VRAM, making them available to the GPU with less wait times.

In order to use RBAR, certain requirements must be met:
  • compatible graphics card (currently in Hackintosh only AMD 6000 series)
  • motherboard with this option in BIOS
  • compatible CPU (Intel 9-10-11 generations and AMD Zen 3 series).
Note: really almost any GPU supports resize bar but most likely they do not benefit from the performance improvement.

OpenCore 0.7.4 has added support for RBAR by adding 2 quirks:
  • Booter >> Quirks >> ResizeAppleGpuBars: reduces GPU PCI BAR size to be compatible with macOS.
  • UEFI >> Quirks >> ResizeGpuBars: configure the GPU PCI BAR size for systems other than macOS.
ResizeAppleGpuBars affects only to macOS and ResizeGpuBars affects all other operating systems.

Note from vit9696: ResizeAppleGpuBars should be 0 for boards supporting resize bar and -1 for boards that do not. 9 and 10 will cause sleep wake crashes on macOS with most GPUs and 8 will cause excessive memory usage on some GPUs without any useful benefit.
 
Last edited:
I have tested the Unigine Valley benchmark in the 2 modes on my system (Coffee Lake R CPU and RX580 GPU):
  • Above 4G Decoding and Resize BAR disabled + ResizeAppleGpuBars = -1
  • Above 4G Decoding and Resize BAR enabled + ResizeAppleGpuBars = 0.
There is a slight increase in the number of frames per second, the minimum value increases approximately 20% and the maximum value 10%, without changes in the GPU temperature.

@Ben42
After more tests, I have seen that there is really no appreciable improvement in macOS when activating ReBAR, scores are the same with and without ReBAR.
The explanation can be: the RX580 GPU does not support ReBAR or, if it does, it does not benefit from it.
 
Last edited:
I have tested the Unigine Valley benchmark in the 2 modes on my system (Coffee Lake R CPU and RX580 GPU):
  • Above 4G Decoding and Resize BAR disabled + ResizeAppleGpuBars = -1
  • Above 4G Decoding and Resize BAR enabled + ResizeAppleGpuBars = 0.
There is a slight increase in the number of frames per

second, the minimum value increases approximately 20% and the maximum value 10%, without changes in the GPU temperature.
That is a pretty good increase with just a small config.plist tweak...but didn't you wrote that only big navi cards are compatible with this? So it can be used for other cards as well?

Edit:
When you don't read the whole thing and just skim through it. :)

I see now that it can be enabled with any card.
 
Last edited:
Hello .
For automatic upgrade to OS Monterey you need the new version of OpenCore, right?

The only way to have the config.pslist updated is to make a manual compare with "OCConfigCompare"?
There is no wizard?

I tried but with poor results.
HELP please.

I enclose my EFI.

It is always a pleasure to hear from you,
:)
 

Attachments

  • EFI.zip
    9 MB · Views: 226
Hello .
For automatic upgrade to OS Monterey you need the new version of OpenCore, right?

The only way to have the config.pslist updated is to make a manual compare with "OCConfigCompare"?
There is no wizard?

I tried but with poor results.
HELP please.

I enclose my EFI.

It is always a pleasure to hear from you,
:)
compare your config.plist with the sample.plist from opencore and make the needed changes
 
That is a pretty good increase with just a small config.plist tweak...but didn't you wrote that only big navi cards are compatible with this? So it can be used for other cards as well?

Edit:
When you don't read the whole thing and just skim through it. :)

I see now that it can be enabled with any card.
But this occurs in a very demanding graphical test, with GPU's memory and processor at maximum. In a more regular scenario (desktop, internet, image editor, video playback...) I don't see appreciable improvements.
 
But this occurs in a very demanding graphical test, with GPU's memory and processor at maximum. In a more regular scenario (desktop, internet, image editor, video playback...) I don't see appreciable improvements.
I understand, but if it's there why not use it. I use Photoshop, Illustrator, Blender, and Esko Studio Visualiser for 3D. Those apps and my workflow tend to task the system pretty seriously.
 
I understand, but if it's there why not use it. I use Photoshop, Illustrator, Blender, and Esko Studio Visualiser for 3D. Those apps and my workflow tend to task the system pretty seriously.
You are right. Moreover, if using windows, now it's possible to have rbar activated in windows and macos, windows was rbar capable but macos wasn't until now.
 
@ifreddy
Config.plist seems to be ok for 0.7.5. What bad result are you getting?

Note: I always check config.plist against ocvalidate tool, included in OpenCore package. Your file has passed ok.
 
Monthly message by vit9696, please read it carefully, there is no better place to see what's new in OpenCore.
https://dortania.github.io/hackintosh/updates/2021/11/01/acidanthera-november.html

Main changes applied in 0.7.5 version:
  • Improved Linux boot and revised OpenLinuxBoot documentation
  • Fixed external drive icons
  • Updated builtin firmware versions for SMBIOS
  • Updated recovery downloading commands to include Big Sur and Monterey
  • Added support for GPU Resize BAR (RBAR).

config.plist
  • Booter >> Quirks >> ResizeAppleGpuBars (integer) whose default value is -1 (disables this quirk); reduces GPU PCI BAR size to be compatible with macOS.
  • UEFI >> Quirks >> ResizeGpuBars (integer) whose default value is -1 (disables this quirk); configure the GPU PCI BAR size for systems other than macOS; leaving it at -1 prevents this value from being applied by OpenCore to Windows or Linux.
Kexts
  • AppleALC 1.6.6 (new layouts added)
  • BrcmPatchRAM 2.6.1 (Improved BlueToolFixup compatibility with macOS 12) *
  • HibernationFixup 1.4.5 (improved behaviour when battery level is critical)
  • Lilu 1.5.7 (improved support for all 64-bit macOS versions)
  • VoodooPS2 2.2.7 (fixes)
  • VoodooRMI 1.3.5 (fixes, added new devices)
  • WhateverGreen 1.5.5 (improved backlight control in AMD RX 5000 series, fixed black screen in Skylake and newer).
* Monterey has brought major problems for third-party (non-native Apple) wifi and bluetooth devices. Developers are working hard to fix these problems. Little by little improvements are being made but we are still not 100%.

Notes about Resizable BAR (base address register)

Resizable BAR (RBAR) is a technology included in the PCI Express 3.0 specification since 2008 but until now it has been very little used. In AMD it is called Smart Access Memory (SAM). Its purpose is to increase the amount of VRAM (graphics card memory) that is accessible by the CPU. The limit has been kept at 256MB of VRAM memory for backward compatibility.

What RBAR does is allow the CPU to access all of the VRAM memory. The only restriction is imposed by the GPU itself. In theory the CPU can access all the VRAM but in practice the GPU always has the priority of use.
Its main advantage is in graphically demanding games. In this type of game, the CPU collaborates with the GPU performing the necessary calculation tasks for the execution of the game. Without RBAR, the CPU can only load 256MB into VRAM and the rest has to be loaded into RAM, which slows down the GPU from reading the data. With RBAR, all or most of the computational tasks performed by the CPU are stored in the VRAM, making them available to the GPU with less wait times.

In order to use RBAR, certain requirements must be met:
  • compatible graphics card (currently in Hackintosh only AMD 6000 series)
  • motherboard with this option in BIOS
  • compatible CPU (Intel 9-10-11 generations and AMD Zen 3 series).
Note: really almost any GPU supports resize bar but most likely they do not benefit from the performance improvement.

OpenCore 0.7.4 has added support for RBAR by adding 2 quirks:
  • Booter >> Quirks >> ResizeAppleGpuBars: reduces GPU PCI BAR size to be compatible with macOS.
  • UEFI >> Quirks >> ResizeGpuBars: configure the GPU PCI BAR size for systems other than macOS.
ResizeAppleGpuBars affects only to macOS and ResizeGpuBars affects all other operating systems.

Note from vit9696: ResizeAppleGpuBars should be 0 for boards supporting resize bar and -1 for boards that do not. 9 and 10 will cause sleep wake crashes on macOS with most GPUs and 8 will cause excessive memory usage on some GPUs without any useful benefit.
After updating to OC 0.7.5 yesterday, I enabled Resize BAR in BIOS, and set ResizeAppleGpuBars to 0 in my conflig.plist. So far, so good.

You also mention that ResizeGpuBars affects all other operating systems; does this pertain to Windows? I've got Win11 on a separate SSD and after enabling Resize BAR in BIOS and booting into Windows, I got a notice that my graphics driver "needed to be updated" and that I had to restart Windows to accomplish that. After restarting, I noticed that the Radeon Software Adrenaline app showed that Resize BAR was enabled. All good there.

It seems that Windows took care of the needed adjustments all by itself, so do I need to edit the value for ResizeGpuBars in my config.plist, anyway, or would that just be for some other OS entirely?
 
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