We have mentioned in some articles attached to this one the technology developed by NVIDIA and from which it competes with AMD and its SAM project. Ultimately, the two technologies have a common basis, so while the approach to it is different, they tend to be the same. But many of you will also be wondering what the resizable bar is and why is it on everyone’s lips.
Resizable BAR or ReBAR, goodbye the bottleneck between CPU and GPU
While this technology came from another that was already attached to it like 4G decoding, something all motherboards have been bringing for years, until now there was no GPU support available.
Resizable BAR, therefore, is the name given to NVIDIA’s technology to unlock something that was previously unthinkable: removing the limit of 256MB per block of texture size, so that the CPU, RAM, and GPU with their VRAM now have full access to the PCIe bus, with no limits.
And it is that the complexity of this technique was precisely to make these three components limitless thanks to an interface as widely used as PCIe. As we play any game, it requires textures which are worked by the CPU, loaded from the SSD, stored in the RAM to act as a fast intermediary between it and the VRAM and at the same time the GPU needs information from the latter.
It’s a chain of command where everything has to work synchronously, so limiting such bandwidth as until now was just an obstacle for the PCIe interface itself and for NVIDIA and AMD. The transfer between CPU and GPU is constant, but in 256MB blocks it may require a number of small transfers which crash the CPU and sometimes the GPU does not have the information in time.
Acceso total al frame buffer
The limitation was derived as we say through PCIe and both companies, but at the same time Intel and AMD had to collaborate as well as manufacturers to support this technology, so it’s not something that can be activated on all platforms.
The reduction in information and texture transfers, either with the CPU or extracted in RAM cache from the system RAM memory means that any asset or resource can be requested as needed and at the same time it can be sent in its entirety. . , without any restriction. This is achieved by limiting the bandwidth of the frame buffer, which means fewer or no queues, so milliseconds are reduced and performance is gained.
The processor can work more information, better organized, in better sectioned frames due to their larger size, so it is more efficient than sending small packets of information. This makes, at the same time, the requests for textures to the RAM are also more efficient, since it is possible to download from it and to the GPU of any size, regardless of its size and in once or even split into packets larger than 256MB.
What do we need to be able to benefit from ReBar?
As a proprietary technology, NVIDIA gives us a series of instructions to activate the resizable bar:
- Confirm that you have a compatible processor and processor chipset.
- Confirm that you have a compatible motherboard.
- Update the ball’s BIOS, if necessary (if we haven’t installed the latest version available it will be), by installing a manufacturer update. Next, enable ReBar support in the BIOS interface.
- Update to the latest GeForce Game Ready driver (version 465.89 WHQL and later) or later
- If you own a GeForce RTX 3060, you’re good to go. If you have a GeForce RTX 3060 Ti, 3070, 3080, or 3090, you might need an updated GPU BIOS (almost certainly).
- If you have an NVIDIA Founders Edition graphics card, get your VBIOS update tool directly from our website. If you have a personalized membership card, get the update tool from their site. Make sure the resizable bar is enabled in the NVIDIA Control Panel.
All major motherboard manufacturers currently support the latest platforms and some that were already EOL. To be precise, support is defined like this:
To this must be added Intel’s eighth and ninth generation processors as well as the Z370 and Z390 chipsets, which have just received support after pressure from users. As if that weren’t enough, the list of games, while concise, grows longer, with its main benefactors being the following titles:
This list is growing bit by bit, so it is possible that at the time of reading this article there are more games available with support. This is something from NVIDIA and especially the developer of the title, who are working hard to implement this improvement in their engines.
How to make sure the resizable bar is active
If we have one of the named or newer GPUs, if we have a newer driver than the one mentioned and a BIOS on our card compatible and with updated ReBar, then we can go to the NVIDIA control panel, click on the system information and we can see a section that specifically receives the name of this technology: RESIZABLE BAR.
If it says “Yes” or “Yes” then it is active and we can take advantage of the free performance improvement it offers us in the 17 compatible titles.