What Is Resizable BAR? Free FPS Boost for Your GPU

The quick answer to what is resizable bar is a Resizable BAR (Base Address Register) is a PCIe feature that lets your CPU access your entire GPU memory at once. Without it, the CPU can only access small 256MB chunks at a time. This improves performance in many games.

How Resizable BAR Works

Your GPU has its own memory (VRAM) for storing textures, models, and other game data. The CPU needs to access this data to tell the GPU what to render.

Traditional systems limit this access to 256MB windows. The CPU must make multiple requests to access data spread across VRAM. Resizable BAR removes this limit, letting the CPU access all VRAM in one go.

This reduces CPU overhead and can improve frame rates, especially in open-world games that constantly stream new assets.

Resizable BAR vs Smart Access Memory

They are the same thing. Resizable BAR is the official PCIe specification name. AMD markets it as Smart Access Memory (SAM). NVIDIA calls it Resizable BAR. Intel uses the standard name.

The technology works identically regardless of branding. It requires compatible CPU, GPU, motherboard, and BIOS.

Performance Gains

Performance improvement varies by game. Some games see 5-15% FPS gains. Others show no difference. A few games actually perform slightly worse.

Games that benefit most:

• Open-world games with frequent asset streaming
• Games with large textures and detailed environments
• Situations where CPU is partially limiting GPU performance

Check if your CPU and GPU pairing is balanced. Resizable BAR helps most when CPU overhead is a factor.

Requirements for Resizable BAR

CPU: AMD Ryzen 3000 series or newer. Intel 10th gen or newer.

GPU: NVIDIA RTX 30 series or newer. AMD RX 5000 series or newer. Intel Arc.

Motherboard: Must support Resizable BAR in BIOS. Most motherboards from 2020 onward support it after BIOS update.

BIOS Settings: Above 4G Decoding must be enabled. Resizable BAR or SAM must be enabled.

How to Enable Resizable BAR

1. Update motherboard BIOS to latest version
2. Update GPU drivers to latest version
3. Enter BIOS setup (usually Del or F2 at boot)
4. Enable “Above 4G Decoding” (required)
5. Enable “Resizable BAR” or “Smart Access Memory”
6. Save and exit BIOS

Verify it is working using GPU-Z. The “Resizable BAR” field should show “Enabled” under the Graphics Card tab.

Should You Enable Resizable BAR?

Yes. There is no downside to enabling it on compatible systems. Even if a specific game does not benefit, you lose nothing. The games that do benefit can see meaningful FPS improvements.

If you experience instability after enabling, update your BIOS and GPU drivers first. Rarely, certain configurations may need it disabled for stability.

Conclusion

Resizable BAR is essentially free performance on compatible systems. It requires no additional cost, takes minutes to enable in BIOS, and delivers measurable FPS gains in many modern games.

While not every game benefits equally, the ones that do can see 5-15% improvements. Since there is no downside to enabling it on supported hardware, every compatible PC should have Resizable BAR turned on.

If you are building a new system or upgrading your GPU, ensure your motherboard BIOS is updated and Resizable BAR is enabled. It is one of the easiest performance optimizations available, and leaving it disabled means leaving free frames on the table.