New desktop GPUs will have to wait another month for support.
Nvidia has finally started rolling out Resizable BAR support, starting with the RTX 3060 desktop and a select few RTX 3000-series laptops. Enabling it may be a bit of a hassle, but it’s a free update, so it’s going to get a thumbs up.
Resizable BAR is a PCIe standard feature that allows a system CPU to display the entire memory subsystem of the GPU instead of just a small 256 MB portion. Implementation of the functionality includes low-level support in the Processor, motherboard, and GPU, which is how AMD, which designs all three, was the first to market the Resizable BAR implementation named SAM (smart access memory).
In our research, allowing SAM on the RX 6800 could increase the game’s average frame rate by up to 20% or damage it by up to 10%. In most names, however, making the feature did almost nothing, which is reflected in the average improvement: just 3%.
Understandably, then, Nvidia is taking another path. Their drivers will keep the Resizable BAR disabled by default, and only switch it to titles where Nvidia has found that it enhances performance. As far as writing is concerned, these 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, Resizable BAR will increase performance “from a few percent to 10 percent.” At the end of March, when the rest of the RTX 3000 series receives support for the Resizable BAR, more games will be added to the list. The selective approach of Nvidia is undeniably a good idea (if done correctly) but, sadly, it is a benefit that is negated by the difficulty of allowing the Resizable BAR.
In laptops, the situation is all right but not great: some laptops will come with the Resizable BAR allowed, some won’t, and there’s nothing you can do about it. Nvidia says, “Check with each laptop manufacturer to see if Resizable BAR is supported on a specific model.”
Desktop accessibility is a 3D chess game. Enabling Resizable BAR, or, equally likely, finding that your device does not support it, is a five-step procedure. First, you’ll need to verify if your CPU is compatible: all AMD 5000-series CPUs are compatible with all 10th-gen Intel processors, but only the i5, i7, and i9-series from the next 11th-gen will be compatible. Simple enough…
Step two: check the chipset on your motherboard. The AMD 500-series chipsets are compatible and the 400-series chipsets are compatible with the Ryzen 5000-series CPUs on motherboards. The 500-series Intel chipsets announced as writing are all compatible, and so are all their 400-series chipsets. Always with me, huh?
Move three is more troublesome: you’re going to need to upgrade your motherboard SBIOS, so you’re just going to have to hope there’s an update. According to Nvidia, “The following manufacturers are offering SBIOS updates to select motherboards to allow Resizable BAR with GeForce RTX 30 series desktop graphics cards: Asus, Asrock, Colorful, EVGA, Gigabyte, and MSI.”
Fourth, you’ll need to upgrade your VBIOS GPU, unless you’re one of the lucky few with the latest RTX 3060. For Founder’s Edition owners, Nvidia will provide the update itself, but anyone else will need to download the update from their GPU manufacturer’s website.
And the home stretch: upgrade your GPU drivers. After that, you can check whether the Resizable BAR is functioning correctly in the Nvidia Control Panel, in the Device Details tab.