If you play PC games, design 3D models, or edit video , you're likely interested in squeezing out every last FPS and eliminating any bottlenecks between your CPU and GPU. In recent years, a feature of the PCI Express standard called Resizable BAR has become very popular precisely for this reason. It allows you to improve graphics performance without spending more money on hardware, simply by enabling a hidden option in the BIOS and tweaking a couple of settings in Windows.
This guide is designed for those who want to learn how to enable Resizable BAR, verify that it actually works, and understand the extent of its impact on games and professional workloads. We'll cover everything from basic theory to CPU, GPU, and motherboard compatibility, how to enable it step by step, and how to measure its real-world impact on your system.
What exactly is a Resizable BAR and why does it matter?
Resizable BAR (Base Address Register Resizable) is an advanced feature of the PCI Express bus that allows the CPU to access all of the graphics card's memory (VRAM) at once, instead of in small 256 MB blocks as has been the traditional practice. This historical limitation results in more requests, higher latency, and ultimately, lower FPS and more stuttering in demanding games.
- Without Resizable BAR enabled, communication between CPU and VRAM functions like a funnel. The system can only see a 256MB chunk of GPU memory through a fixed BAR register. If the game needs huge textures, complex models, or shader data, it has to request chunks one after another.
- With Resizable BAR enabled, that limit becomes dynamic and resizable. The system can map a much larger portion of VRAM in a single access, and even work with multiple buffers in parallel. In practice, this allows the CPU to manage textures, geometry, and shader data more efficiently, reducing bottlenecks and improving overall performance.
This technology isn't new on paper. It's been part of the PCIe specification since version 2.0 and was solidified with PCIe 3.0, but until the arrival of NVIDIA GeForce RTX 30 series GPUs, AMD Radeon RX 6000 series GPUs, and modern Intel and AMD CPUs, virtually no one was taking advantage of it. Now, manufacturers have fine-tuned BIOS, VBIOS, and drivers to leverage it and present it as a "free" performance boost.
How Resizable BAR works under the hood
The full name, Resizable Base Address Register, aptly describes the concept. It's a PCIe device register that indicates which portion of the GPU's memory is visible to the CPU at any given time. Previously, this register had a practical size of 256 MB. Now, it can be scaled to several gigabytes, provided the hardware and firmware support it.
With Resizable BAR enabled, the addressable area size can be dynamically increased , so the CPU has a much larger portion of VRAM visible in a single mapping operation. This minimizes repetitive transfers and allows more requests to be handled in parallel, especially with PCIe 4.0 x16, which offers up to 31,5 GB/s of theoretical bandwidth.
In practice, this means that a GPU with 24 or 32 GB of VRAM can transfer enormous amounts of data to the CPU in very short periods. In open-world games or titles with frequent scene changes, the engine can load entire texture maps, character models, animations, and environmental effects with fewer interruptions.
Smart Access Memory from AMD, Resizable BAR from NVIDIA and Intel Arc
AMD, NVIDIA, and Intel have all adopted this PCIe feature, each with its own brand name and compatibility logic. However, they all aim for the same goal: to free the CPU from the 256MB restriction and allow it to access significantly more VRAM at once.
- AMD Smart Access Memory (SAM) is AMD's marketing label for the same feature. It was originally promoted as an advantage of Ryzen 5000 + Radeon RX 6000 combinations, but over time support has been extended to more Ryzen processors and motherboards with 400 and 500 series chipsets. And even some of the Ryzen 3000 family.
- NVIDIA, for its part, simply refers to the NVIDIA Resizable BAR and it offers it on all GeForce RTX 30 series cards. In their case, they also activate the feature only in a specific list of tested and validated games to avoid performance losses in older or poorly optimized titles.
- Intel has also jumped on the bandwagon with its Arc GPUswhich natively support this functionality in combination with recent Core processors and compatible motherboards. Although the ecosystem is still younger, the premise is the same: improve CPU-GPU communication to gain fluidity without changing the main hardware.
The key is understanding that this improvement comes from leveraging a capability of the PCIe standard that all stakeholders have now decided to promote. That's why you need the entire chain (CPU, chipset, BIOS, GPU, VBIOS, operating system, and drivers) to be on the same page.
Hardware requirements and system compatibility
Regarding GPUs, the basic requirements are: NVIDIA GeForce RTX 30 series or higher (3060 and above), AMD Radeon RX 6000 series or later, and Intel Arc A-series, which already include this capability. Any earlier model is typically not officially supported.
Regarding the CPU, you need a relatively recent processor. For Intel, this typically means starting with the 10th generation Core processors and above, with particularly robust support for the 10th and 11th generations. For AMD, the entire Ryzen 5000 series (Zen 3) and a large portion of the Ryzen 3000 series are considered compatible.
The motherboard chipset is also a determining factor . For Intel, 500 series chipsets and models like Z490, H470, B460, or H410 can handle Resizable BAR after the corresponding BIOS update. For AMD, 500 and 400 series chipsets with support for Zen 3 and AGESA 1.1.0.0 or higher are usually compatible, although each motherboard manufacturer has its own limitations.
Another essential requirement is that the motherboard BIOS has full UEFI support and allows you to enable "Above 4G Decoding" along with "Resizable BAR" or "Re-Size BAR Support". If your system is still running in Legacy BIOS mode with MBR partitions, you'll need to switch to UEFI and GPT for the option to work correctly.
How to enable Resizable BAR step by step in the BIOS
Once hardware, system, and partition compatibility are confirmed , it's time to enter the BIOS/UEFI and adjust the key settings. The exact path depends on the manufacturer, but the general procedure is very similar on most modern motherboards.
To access the BIOS, restart your computer and press the corresponding key during startup . On desktop motherboards, this is usually Delete, while on many brand-name computers, such as HP OMEN, it's F10 (or Esc followed by F10). If you have a BIOS password, enter it when prompted.
Once inside, switch from EZ or basic mode to advanced mode to see all the options. On ASUS motherboards, for example, in EZ mode on a TUF GAMING X570-PLUS, you'll find a specific icon called "Resizable BAR" that lets you enable the feature with a click. On other models, you'll need to navigate to the "Advanced," "PCIe Settings," or "System Options" tab.
The two key options you need to locate and enable are: “Above 4G Decoding” and “Resizable BAR” (or “Re-Size BAR Support”). The first must be set to “Enabled,” as without it the system cannot allocate the expanded address space required for VRAM on 64-bit systems. Then, set Resizable BAR to “Enabled” or “Auto,” depending on the manufacturer's settings.
Once you've made the necessary changes, save and exit the BIOS using F10 or the "Save & Exit" option. The computer will restart. If everything is configured correctly, the operating system should boot with the Resizable BAR operational, ready to be tested from the GPU drivers or with external tools.
Confirm that Resizable BAR is active in Windows
Enabling the option in the BIOS is only half the story. It's also essential to verify in Windows that the graphics card and drivers have recognized and are using the feature. Fortunately, both NVIDIA and AMD, as well as third-party utilities, offer easy ways to check this status.
In the NVIDIA Control Panel, right-click on the desktop and select the corresponding option . Once open, go to the "Help" menu and then to "System Information." In the window that appears, look for the "Resizable BAR" field: if it says "Yes," the feature is correctly enabled for your GeForce RTX 30 series; if it says "No," you'll need to review the previous steps.
If you're using an AMD Radeon graphics card, open the AMD: Adrenalin Edition software . Click the gear icon to access the settings and go to the "Graphics" tab. There you should see the "Smart Access Memory" section. Once your system meets all the requirements, you can enable it and check if it's listed as "Enabled."
GPU-Z is a very handy universal tool for this check . Download it from the TechPowerUp website, run it (ideally as administrator), and in the main window you'll see a specific field called "Resizable BAR" that will indicate whether it's "Enabled," "Disabled," or if the system doesn't meet any of the requirements.
How much performance can you actually gain with Resizable BAR?
Manufacturers are boasting improvements of up to 12-15% in some very specific configurations. NVIDIA reports increases of around 12% with an RTX 3080 in selected titles. AMD, for its part, has mentioned figures around 15% with Smart Access Memory in certain scenarios.
However, independent tests show more modest results . Specialized media outlets like TechPowerUp have measured around a 3-4% average improvement in games officially supported by NVIDIA Resizable BAR, and barely 1-2% in titles that aren't on the list but can still run with the feature enabled.
In the case of AMD, analyses like those from PCWorld using an RX 6900 XT indicate an average increase of around 5%, with some notable examples like Borderlands 3 at 1440p, where an increase of nearly 8,4% was observed. It's not a revolution, but it is a free boost that complements other optimizations.
The good news is that trying it costs virtually nothing. If you meet the hardware and firmware requirements, you activate the feature, run a couple of benchmarks with and without Resizable BAR, and decide based on the data. Essentially, it's "free" performance, limited only by your PC's ecosystem and driver maturity.
Use in pre-built PCs and gaming laptops (OMEN, etc.)
Many current brand-name devices, especially those geared towards gaming and creation , already come factory-prepared to take advantage of Resizable BAR.
In slightly more modest ranges, such as PCs with RTX 4070, RTX 4060 Ti or Radeon RX 7600 , compatibility is also usually complete, and the system comes with BIOS and drivers ready to activate the function from day one, without needing to flash anything manually, beyond keeping the equipment updated.
In gaming laptops, such as many OMEN laptops equipped with RTX 4090, 4080, 4070, or 4060 GPUs, Resizable BAR is already supported by design. This is especially useful here because the hardware operates in a more confined thermal space, and any improvement in CPU-GPU communication efficiency helps to better utilize the thermal budget without overheating the system.
On these systems, tools like OMEN Gaming Hub allow you to monitor the impact of the feature . You can run a performance test with Resizable BAR disabled, enable it in the BIOS, run the benchmark again, and compare temperatures, FPS, and stability, all from a single panel, making it easy to decide whether to leave it always active or not.
Measuring impact: benchmarks and monitoring
To determine if Resizable BAR is adding value in your specific case , the ideal approach is to take measurements before and after under controlled conditions. This involves maintaining the same graphics settings, resolution, and test scenario, and only changing the function's state.
You can use built-in benchmarks in games like Cyberpunk 2077, Assassin's Creed Valhalla, or Red Dead Redemption 2 , which are also officially on the list of NVIDIA-compatible titles. Run several passes of each benchmark with the feature disabled, note the average, minimum, and maximum FPS, and repeat the process with Resizable BAR enabled.
Tools like OMEN Gaming Hub, MSI Afterburner, or the Windows Performance Monitor let you track not only FPS, but also GPU usage, CPU usage, temperature, and power consumption. If you see a slight increase in FPS and a more balanced load, it's a good sign that Resizable BAR is alleviating bottlenecks.
In professional workloads, such as video or 3D editing , you might look at render times, timeline preview speed, viewport smoothness in Blender or Maya, or performance in engines like Unreal Engine 5. Often the improvement is felt more in smoothness and responsiveness than in raw performance figures.
If you notice that any game performs worse after activating the feature (dropped FPS, new micro-stuttering, graphical errors), the best option is to disable Resizable BAR only for that title from NVIDIA Profile Inspector or the AMD panel, while keeping it active globally for the rest of your library.
Best practices to get the most out of Resizable BAR
Basic PC health monitoring helps detect problems early . Keep an eye on CPU and GPU temperatures, performance in your benchmark games, and overall stability whenever you make significant changes, such as new drivers or overclocking adjustments combined with Resizable BAR.
In many cases, it's a good idea to perform a clean installation of your graphics drivers. Tools like DDU (Display Driver Uninstaller) can be used for this when upgrading to a newer version. This avoids lingering conflicts and ensures that Resizable BAR is implemented as cleanly as possible.
All of this works even better if the rest of the hardware is up to par . A fast NVMe SSD minimizes loading times. It also complements the improved data transfer. Having at least 16 GB of RAM (and preferably 32 GB if you work with 4K, editing, or 3D) and using relatively fast memory (DDR4 3200 MHz or higher, or modern DDR5) also helps prevent the CPU from becoming the new bottleneck. Furthermore, you can learn how to compress RAM to better utilize resources on systems with less memory.
Finally, combining Resizable BAR with moderate GPU and CPU overclocking, active XMP/DOCP profiles, and system game modes often yields a small performance boost, provided you keep temperatures and stability under control. The key is to proceed gradually and thoroughly test each change before implementing several at once.
Quick FAQs about Resizable BAR
- Does Resizable BAR work with older graphics cards? Generally no. A minimum of an NVIDIA RTX 30 series, an AMD Radeon RX 6000, or an Intel Arc GPU is required.
- Can I use this technology on a laptop? Yes, provided the laptop meets the GPU, CPU, and BIOS requirements. Many recent gaming laptops (especially dedicated series like OMEN and other gamer-oriented models) come with it ready to use.
- Do all games benefit equally? No. Many modern titles show clear improvements, others barely change, and a few may perform worse. NVIDIA, for example, maintains a closed list of officially compatible games, which includes Assassin's Creed Valhalla, Battlefield V, and others.
- Is Resizable BAR the same as AMD Smart Access Memory? Essentially, yes. SAM is the name AMD gives to its implementation of the same PCIe feature, although the way to activate it and the supported hardware combinations are decided by each manufacturer.
- Do I need to activate it on both the motherboard and the graphics card? You don't need to manually "turn on" anything within the GPU, but you do need the card's VBIOS and drivers to be ready. On the motherboard, you must enable "Above 4G Decoding" and "Resizable BAR" in the BIOS; without them, the feature won't work even if the graphics card is compatible.
The great advantage of Resizable BAR is that it offers extra performance and smoothness without requiring additional components , provided your PC is already within the supported generations. It might not transform your system overnight, but combined with well-tuned drivers, BIOS, and fast storage, this technology helps smooth out the experience in demanding games and complex creative projects. This way, your system is ready for what's coming in the next few years.
