About a month ago, NVIDIA announced that it would bring resizable BAR support to its RTX 30 Series laptop parts, as well as to the RTX 30 Series desktop and with its GeForce Game Ready 461.72 driver, they did just that. But for now, it is somewhat limited with only the supported mobile SKUs and a single part of the desktop, the RTX 3060.
In short, the resizable BAR removes the strong restriction on the amount of data that can flow between the CPU and the GPU memory and can sometimes allow for substantial performance increases. The resizable BAR grew in popularity and recognition when AMD implemented smart access memory when you paired a 5000 Ryzen series CPU and a 500 series chipset with an RX 6000 series GPU. The biggest difference here between the implementation of AMDs and NVIDIAs is that NVIDIA support for ReBAR (scalable BAR) is that it is compatible with many other platforms.
In fact, NVIDIA has extended support for ReBAR even for PCIe Gen 3.0 platforms, supporting Intel’s 10th Generation Core CPUs with the 400 series chipsets that are now available. Interestingly, support for AMD CPUs includes only the Zen 3 Ryzen 5000 Series, indicating that there is more than just switching a switch, but they show support even for 400 series chipset motherboards, as long as the BIOS is supported.
Test setup
Test System
| Components | X570 |
|---|---|
| CPU | Ryzen 9 5900X (stock) |
| Memory | 32 GB Hyper X Predator DDR4 3600 |
| Motherboard | ASUS TUF Gaming X570 Plus-WiFi |
| Store | TeamGroup Cardea 1TB NVMe PCIe 4.0 |
| PSU | Cooler Master V1200 Platinum |
| Windows version | Latest version of Windows at the time of testing |
| Hardware-accelerated GPU scheduling | Enabled if compatible with GPU and driver. |
One of the interesting moves with the addition of NVIDIA’s support for BARRA RESOLVEIS is that they are being selective about which games are supported and this is being done through the drivers. Why do you ask? Well, for example, in tests done by Hardware Unboxed, we saw where AMD’s implementation of Smart Access Memory can sometimes lead to no performance benefit or even performance degradation. Currently, the list is quite limited, but it is expected to grow rapidly as we see support expand to other cards. Games are supported;
- Assassin’s Creed Valhalla
- Battlefield V
- Borderlands 3
- Forza Horizon 4
- Gears 5
- Metro Exodus
- Red Dead Redemption 2
- Watch Dogs: Legion
Results RTX 3060 12GB BAR resizable 1440p
Conclusion
NVIDIA limiting game support at launch may have seemed strange, but it looks like they are looking to launch support for games that only benefit from the feature. In our results, we saw a 4-11% increase in performance, something often not even achieved by heavy overclocking. This is a welcome result and the fact that it will be updated via drivers and whitelisted games means that you won’t have to worry about whether a game will lose performance due to the resizable bar feature enabled in the BIOS.
Support for scalable BAR on much more sophisticated cards will obviously be attractive, but in this more affordable price segment (although now is a bad time to say it) this is where things really start to change technology like this. The combinations of scalable BAR, Mesh Shaders, VRS and even DLSS can really transform the expectations of mid-range offerings. When the dust settles due to availability issues, I have a feeling that things like smart access memory and resizable bar will need to be shown in performance comparisons because they are usually too big to be ignored by shoppers.
Detailing performance in the video card space is becoming exponentially more complicated these days, with all the great new features coming to all DX12 Ultimate compatible GPUs which is becoming quite exciting, as long as we can actually buy them .