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Last reply by 12-05-2022 Unsolved
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7 Gold

What is Nvidia Resizable BAR VBIOS support?

I see Resizable BAR mentioned in forum from time to time but had no idea what is. A google search here tells me this is what it is:

Resizable BAR utilizes an advanced feature of PCI Express to increase performance in certain games. As of March 30th, 2021, Resizable BAR is supported for GeForce RTX 30 Series graphics cards and laptops.

For desktops to take advantage of Resizable BAR, users need a GeForce RTX 30 Series graphics card with a supported VBIOS, a compatible CPU, compatible motherboard, motherboard SBIOS update, and our newest GeForce Game Ready driver.

For GeForce RTX 30 Series laptops, please check with the manufacturer to see if Resizable BAR is supported on a specific model.

For instructions on how to enable Resizable BAR, continue reading

Resizable BAR is an optional PCI Express interface technology. As you move through a world in a game, GPU memory (VRAM) constantly transfers textures, shaders and geometry via many small CPU to GPU transfers.

With the ever-growing size of modern game assets, this results in a lot of transfers. Using Resizable BAR, assets can instead be requested as-needed and sent in full, so the CPU can efficiently access the entire frame buffer. And if multiple requests are made, transfers can occur concurrently, rather than queuing. 

Replies (2)
6 Indium

As far as compatible CPU, you don't need a compatible CPU. I know Nvidia has a table where they explain the compatible CPU's, but I can attest that resizable bar works without a problem on a Ryzen 3700X OEM. I had it enabled and fully working on my current system.

Resizable bar support 

I remember back in the day when I had my R10 and I inquired with support why the Ryzen 5000 R10 had resizable bar support but not the Ryzen 3000 R10, and that was the answer: not supported on Ryzen 3000...


What is important is proper BIOS support and the latest game ready drivers. Rebar is actually nothing new and has been part of the PCIe standard for many years.

It really has nothing to do with the CPU because it's part of the PCIe standard, not some CPU standard.


4 Tellurium

Never could get rebar working on my R11/3090 even with the lastest vbios so I gave up. It’s not really used in DCS anyways not that some people are using it but doesn’t seem to be any advantage. 

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