GIGABYTE Releases Resizable BAR Support for AMD 500-series Motherboards via BIOS Updates

erek

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"The latest BIOS of GIGABYTE X570, B550, A520 motherboards has been updated on the website. Users can update to the latest BIOS to motherboards through multiple ways such as GIGABYTE Bios, Q-Flash. Further with the Q-Flash Plus feature, users can easily update BIOS without even installing a processor, memory, graphics cards, so they can enjoy the new BIOS easily and take full advantage of the new processors. Please visit the GIGABYTE official website for more information update."

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https://www.techpowerup.com/275373/...-amd-500-series-motherboards-via-bios-updates
 
What does BAR stand for in this case? Also, it appears to be a beta bios fyi.
Base Address Register.

It is part of the function of the PCI Configuration


"The PCI configuration space consists of up to six 32-bit base address registers for each device. These registers provide both size and data type information. System firmware assigns base addresses in the PCI address domain to these registers.

Each addressable region can be either memory or I/O space. The value contained in bit 0 of the base address register identifies the type. A value of 0 in bit 0 indicates a memory space and a value of 1 indicates an I/O space. Figure A–4 shows two base address registers: one for memory; the other for I/O types."
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For a far more detailed breakdown of how BAR works and its limitations check out section 6.2.5.1 of the PCI specification
 
what would it take for this to work with other AMD CPU's and GPU's?
 
I have a X570 Aorus Elite Wi-Fi, but alas, a 3900x CPU.
 
so am i to understand this all good ONLY if you use or HAVE a 5000 and a 6000 cpu\gpu combo or can i turn it on and how and still get some type of beneifit from it?
 
so am i to understand this all good ONLY if you use or HAVE a 5000 and a 6000 cpu\gpu combo or can i turn it on and how and still get some type of beneifit from it?
For now only Ryzen 5000 and Radeon 6000. Resizable BAR is also coming to Nvidia Ampere cards as well as the Intel Z490 platform. Apparently it is possible to integrate on previous Ryzen CPUs but no word if that is coming.
 
Didn’t feel like making a new thread about it, but ASUS just released a BIOS update for resizable BAR on Z490 boards.

Didn’t think we’d see it THIS quick on non-AMD platforms.

Asus Brings Resizable BAR Support to Z490 Motherboards

Resizable BAR has been a part of the PCIe specification for a very long time, it was one of the optional parts of the 3.0 specification. It was just something that hardware nor software was really capable of using outside of some specialized server environments. So Intel and NVidia should have no issues outside of drivers to enable it for most platforms.
 
Base Address Register.

It is part of the function of the PCI Configuration


"The PCI configuration space consists of up to six 32-bit base address registers for each device. These registers provide both size and data type information. System firmware assigns base addresses in the PCI address domain to these registers.

Each addressable region can be either memory or I/O space. The value contained in bit 0 of the base address register identifies the type. A value of 0 in bit 0 indicates a memory space and a value of 1 indicates an I/O space. Figure A–4 shows two base address registers: one for memory; the other for I/O types."
View attachment 304391

For a far more detailed breakdown of how BAR works and its limitations check out section 6.2.5.1 of the PCI specification
To elaborate on this. Without resizable BAR, a device tells the system how much I/O or Memory address space it needs, and the system allocates space for it, and tells it what addresses to use. Under those constraints, GPUs say they only need 256MB or 512MB, and have to use soem sort of paging to access all the memory on a modern card with gigabytes of memory, because asking for enough space to fully map their memory would cause problems on systems that didn't have enough address space (especially 32-bit systems!).

With resizable BAR, the device tells the system what it's acceptable sizes are (up to 512GB in the 2008 standard extention, even bigger with a later one), and the system can pick which size works best. In that case, you can map the full ram of the card, without needing to do paging trickiery.

My wildass guess (without a lot of GPU knowledge) is games that see a speedup with this were somewhat bottlenecked on the paging elements, and now are free. Games that are seeing fps losses maybe are running out of page cache on the CPU, and have to read the page tables more often, slowing things down.
 
Adding that Gigabyte has released BIOS updates for their Z390 boards, just flashed my AORUS Z390 Pro with a 1/19/2021 BIOS with support for Resizable BAR.
 
I'm to understand that on Asus ROG 570X boards at least (notably the Dark Hero but also earlier ones) this feature is also enabled? Also, we're assuming that "5950XT" is a typo on that slide, right? Or is there credible evidence of an enhanced 5950XT in the works somewhere?
 
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