Nvidia’s has been updated Image ratio That’s not the only way that you can – on paper – give your graphics card performance free back-end boot. Earlier this year, Nvidia started enabling resizable BAR on their laptops and GeForce RTX 30 GPUs, with the promise of faster frame rates at no extra cost. But what exactly is a Resizable BAR, and assuming you have compatible hardware, is it really worth enabling?
In theory, it certainly sounds great: a quick method to unlock greater potential from even best graphics cardand may require at most a few BIOS tweaks to get up and running. The fact that you’re looking at a very small performance gain in the best case – resizable BAR is a cool feature that has the potential to improve, but doesn’t deliver the must-have performance of a technology like DLSS.
What is a resizable BAR?
All gaming PCs generate on-screen images by the CPU processing data – textures, shaders and the like – from the graphics card’s framebuffer. Normally, CPUs can only access this cache in 256MB read blocks, which is obviously not much as modern GPUs typically have 8GB or more video memory.
The resizable BAR essentially makes the entire graphics framebuffer accessible to the CPU at once; where it used to be sipped, now it’s out loud. The idea is that once textures, shaders, and geometry load faster, the game will run faster at a higher frame rate.
If any of that sounds familiar, it could be because AMD beat Nvidia with Smart Access Memory (SAM) in 2020. But branding aside, the resizable SAM and BAR are one and the same: it’s not an AMD or Nvidia technology, but a technology built into the PCIe interface and that hasn’t been used in interface specs since PCIe 3.0.
Even so, there are still some differences. SAM requires both an AMD Ryzen CPU and a Radeon RX 6000 series GPU; The resizable BAR requires an RTX 30 series GPU, but can work with both 10th Gen Ryzens and Intel chips or later. There are other system requirements – not every motherboard chipset will work well with resizable BAR and those may need BIOS updates – but Nvidia’s use of resizable BAR has no hardware limitations like AMD SAM.
However, does it really work?
Ah. Good.
Look, Nvidia has made it clear that not all games give a positive performance, and in their own testing some games actually did drop in performance; for the second, the resizable bar is said to be disabled. But I’ve tested exclusively with games from Nvidia’s whitelist and have never recorded improvements you can really feel.
Most results show BAR resizable by just one or two frames per second, and at 1080p both Horizon Zero Dawn and Watch Dogs Legion take one or three the other way. Again, though, it’s not much more performance than anything it’s sending it through the roof – it doesn’t seem to have much of an effect in these four games.
I suppose the good news here is that there’s very little to be lost from enabling the Resizable Bars. I’ve heard and read before that Watch Dogs Legion could somehow get a big hit despite it being whitelisted, but that wasn’t the case in my testing, so perhaps Nvidia or Ubisoft improved compatibility behind the scenes. And if the effectiveness of the resizable BAR can vary from game to game, that opens up the possibility that future updates and new game releases could see good results. than.
In the absence of any real downside, I’d recommend enabling the resizable BAR, as long as you meet the hardware requirements. With some luck you might be able to drop a few frames more than usual – especially at higher resolutions, from the way it looks – and even if you don’t, you won’t make the output lag. My frame rate is seriously damaged. I admit it’s not the hottest recommendation I’ve ever made, but then it’s hardly the most impactful setting.
How to enable and disable the resizable bar?
Assuming that your CPU, GPU, and motherboard are all compatible and up to date, enabling a resizable BAR requires going to the BIOS. If you’re lucky, like I did with the TUF Gaming Z590-Plus WiFi mobo on my test rig, there might be a handy toggle switch showing up immediately. If so, swipe the switch, save the changes, and exit to restart your PC. The resizable BAR will take effect at startup and you can always use the same method to disable it again.
If it’s not possible to convert easily, look in the BIOS’ advanced settings (most likely in the PCI submenu) for the resizable and above 4G BAR/BAR Encoding settings. Make sure that both are enabled, then go to the Startup menu and disable the Compatibility Support Module (CSM) before saving and exiting. To disable the resizable BAR later, you can just revert any of these changes back to the BIOS.
Be wary of messing with CSM on systems with older memory, be aware: if you installed Windows in the old MBR format instead of the newer GPT, disabling CSM will mean you can’t boot unless you turn it back on or reinstall Windows using the GPT format.
You can check if the resizable BAR is working through the Nvidia Control Panel. Click “System Info” in the bottom left corner and you should see it listed among your GPU details. If marked “Yes”, it will take effect in supported games, and if marked “No”, it is now disabled.
Again, enabling the resizable BAR should have no effect; it just may not help. Hopefully this is something both Nvidia and the game developers can develop into a more powerful upgrade.
