Very early: Nvidia has finally started rolling out BAR Resizable support, starting with the desktop RTX 3060 and some RTX 3000 series equipped laptops. Enabling it can be a bit tricky, but it is a free update so it gets the nod. .
The resizable bar is a feature of the PCIe standard that allows a system’s CPU to see the entire memory subsystem of the GPU, rather than just a small 256MB portion. The feature implementation requires low-level support on the CPU, motherboard, and GPU, which is how AMD, which designs all three, was the first to market with a resizable BAR implementation called SAM (intelligent access memory). .
In our tests, enabling SAM on an RX 6800 could improve a game’s average frame rate by up to 20% or damage it by up to 10%. For most titles, however, enabling the feature did next to nothing, which is reflected in the average improvement: just 3%.
Understandably, then, Nvidia is taking a different route. Your drivers will leave the resizable bar disabled by default and only turn it on in titles where Nvidia found it improves performance. At the time of writing, there are eight titles:
- Assassin’s Creed Valhalla
- Battlefield v
- Borderlands 3
- Forza Horizon 4
- Gears 5
- Metro Exodus
- Red Dead Redemption 2
- Watch Dogs: Legion
In these games, Nvidia says, the adjustable bar can improve performance “from a few percent to 10%.” In late March, when the rest of the RTX 3000 series receives adjustable BAR support, more games will be added to the list. Nvidia’s selective focus is certainly a good idea (if done right) but, unfortunately, it is an advantage that is negated by the complexity of enabling resizable BAR.
On laptops, the situation is fine, but not great – some laptops will come with the adjustable bar turned on, some will not, and there is nothing you can do about it. Nvidia says “check with each laptop manufacturer to find out if the resizable bar is compatible with a particular model.”
Desktop compatibility is a 3D chess game. Enabling resizable BAR, or, equally likely, finding out that your system doesn’t support it, is a five-step process. First, you’ll need to check if your CPU is compatible – all AMD 5000 series CPUs are, as are all 10th Gen Intel processors, but only the next 11th Gen i5, i7, and i9 series will be supported. Simple enough …
Step two: check your motherboard chipset. AMD 500 series chipsets are supported (if not desirable at the moment) and 400 series chipsets are supported on motherboards that are also compatible with Ryzen 5000 series CPUs. 500 series chipsets that Intel announced at the time of writing are all supported, as are all of their 400 series chipsets. Still with me?
Step three is more troublesome: you will need to update the SBIOS on your motherboard, but you will just have to wait for an update. According to Nvidia, “The following manufacturers are offering SBIOS updates for select motherboards to enable the resizable bar with GeForce RTX 30 series desktop graphics cards: Asus, Asrock, Colorful, EVGA, Gigabyte and MSI.”
Fourth, you’ll need to update your GPU’s VBIOS, unless you’re one of the lucky few with a new RTX 3060. For Founder’s Edition owners, Nvidia will provide the update themselves, but everyone else will need to download the update from your GPU manufacturer page.
And the final stretch: update your GPU drivers. You can then check if the resizable BAR is working properly in the Nvidia Control Panel, under the System Information tab.