Disable Multiplane Overlay (MPO)

What it changes

Turns off the Desktop Window Manager multiplane overlay path, where the display controller composes a game window directly instead of the desktop compositor doing it.

Why it helps

• On some GPU, driver, and monitor combinations that path causes intermittent stutter, flickering, or a brief black screen when a borderless game sits on top of other windows.
• This registry value is the workaround NVIDIA documents for those symptoms, and it applies to AMD and Intel systems too.

Trade-offs

• The overlay path normally saves a little GPU work and a little latency, so turn this on only if you actually see the symptoms.
• Newer drivers have fixed most of the original cases.
• Opt-in, off by default, and skipped by Apply Performance Preset.

Requires administrator rights and a restart.

Details

• Sets OverlayTestMode=5 under HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\Dwm. Revert deletes the value, which is the Windows default.

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Part of Performance Tweaks. This page is the same text as the app's Learn more button, generated from Help/tweaks/mpo_disable.md. To fix something, edit that file (or open an issue); wiki edits are overwritten on the next sync.