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How to check and turn on Resizable BAR (Smart Access Memory)

By Michael Steininger · Updated October 2026

Resizable BAR lets the processor access all of the graphics card's memory at once instead of in small windows. AMD calls it Smart Access Memory. In supported games it gives a few percent more performance, and on Intel Arc cards it's essential. It's off on many PCs because it needs a BIOS setting.

Quick answerOpen GPU-Z: Resizable BAR shows Enabled or Disabled. To turn it on, enable Above 4G Decoding and Re-Size BAR Support in the BIOS, with CSM off. Windows must boot in UEFI mode.

1. Check it#

  • GPU-Z (free): the Resizable BAR field on the main tab says Enabled or Disabled.
  • NVIDIA: NVIDIA Control Panel → System Information (bottom left) → Resizable BAR: Yes/No.
  • AMD: AMD Software shows Smart Access Memory as on or off in its graphics settings.

2. What you need#

  • A supported graphics card: NVIDIA RTX 30 series or newer, AMD RX 6000 or newer, Intel Arc.
  • A supported processor and motherboard: in general AMD Ryzen 3000 and newer (most Ryzen 3000 desktop chips except some APUs) and Intel 10th generation and newer, with a recent BIOS.
  • Windows installed in UEFI mode on a GPT disk (the default on PCs from the last years).

3. Turn it on in the BIOS#

  1. Update the BIOS if it's old: support was added in updates for many boards.
  2. Turn CSM (Compatibility Support Module) off. See the warning below.
  3. Turn on Above 4G Decoding.
  4. Turn on Re-Size BAR Support (sometimes called Resizable BAR or Smart Access Memory).
  5. Save and restart, then check GPU-Z again.

The options are usually under PCI subsystem settings or Advanced; the names vary between ASUS, MSI, Gigabyte and ASRock.

WarningTurning CSM off only works if Windows boots in UEFI mode from a GPT disk. Check first: Win + R → msinfo32 → BIOS Mode must say UEFI. If it says Legacy, Windows won't start with CSM off until the disk is converted (Microsoft's MBR2GPT tool). If the PC doesn't start after the change, turn CSM back on.

Questions#

Does Resizable BAR increase FPS?
A few percent in games that benefit, nothing in others. NVIDIA only uses it in games it has tested; AMD uses it more broadly. Intel Arc cards need it for good performance.
Why is Resizable BAR disabled even though my BIOS has it?
Usually CSM is still on, or Above 4G Decoding is off. Both need to be set, and Windows must boot in UEFI mode.
Check it automatically

Frametide's scan checks your PC for setup problems like this one and tells you how many it found (Basic, €12.99 once). Premium (€26.99 once) shows which ones and how to fix them. Its BIOS checks include Resizable BAR, CSM and the memory profile, with where to find them in the BIOS.

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