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How to enable Resizable BAR (Above 4G Decoding) for more FPS

Without Resizable BAR the processor talks to video memory through a small 256 MB window. With it enabled the CPU can access the whole VRAM at once. In many games this gives a few percent more FPS, in some titles more, and costs nothing. NVIDIA calls it Resizable BAR, AMD calls it Smart Access Memory.

What Resizable BAR changes
Off
VRAM
256 MB at a time
On
VRAM
the whole memory

Without it the processor reaches video memory through a small window; with it, all at once.

1. What you need

  • Graphics card: NVIDIA RTX 30 series and newer, AMD Radeon RX 5000 series and newer, or Intel Arc. On early RTX 30 cards a video BIOS (VBIOS) update from the card maker may be required.
  • Processor: AMD Ryzen 3000 and newer, Intel 10th generation and newer.
  • Motherboard: a BIOS version that supports it. Update BIOS first (see our BIOS update guide).
  • Windows installed in UEFI mode on a GPT disk. CSM (legacy mode) has to be off.

2. Check the current state

  • NVIDIA: NVIDIA Control Panel → System Information → Resizable BAR: Yes/No.
  • Any card: GPU-Z shows Resizable BAR: Enabled.
  • AMD: Radeon Software shows Smart Access Memory in the Performance section.

3. Enable it in BIOS

Restart and press Delete (or F2), then F7 for Advanced Mode. You need to do two things: switch off CSM and turn on Above 4G Decoding, then turn on Re-Size BAR Support.

ASUS

  1. Boot → CSM → Launch CSM: Disabled.
  2. Advanced → PCI Subsystem Settings → Above 4G Decoding: Enabled.
  3. In the same menu: Re-Size BAR Support: Enabled (or Auto).
  4. F10 to save and exit.

MSI

  1. Settings → Boot → make sure CSM is disabled (BIOS CSM/UEFI Mode: UEFI).
  2. Settings → Advanced → PCI Subsystem Settings → Above 4G Memory / Crypto Currency Mining: Enabled.
  3. Same menu: Re-Size BAR Support: Enabled.
  4. F10 to save and exit.

Gigabyte

  1. Boot → CSM Support: Disabled.
  2. Settings → IO Ports → Above 4G Decoding: Enabled.
  3. Then Resizable BAR: Enabled (it appears after the previous option is on).
  4. F10 to save and exit.

ASRock

  1. Boot → CSM → CSM: Disabled.
  2. Advanced → PCI Configuration → Above 4G Decoding: Enabled.
  3. Same menu: Re-Size BAR Support: Enabled (or Auto).
  4. F10 to save and exit.

Names vary between boards and BIOS versions. If an option is missing, update BIOS first.

4. If Windows will not start after turning CSM off

This means Windows is installed in legacy (MBR) mode. Turn CSM back on, boot, and convert the disk to GPT with the built-in MBR2GPT tool, then repeat the steps. Make a backup of important files before converting.

5. Check the result

  • GPU-Z → Resizable BAR: Enabled. NVIDIA Control Panel should say Yes.
  • NVIDIA turns the feature on per game from its own list, so the gain differs: it helps in some games and does nothing in others.

6. Manufacturer support pages