Global Fullscreen Optimizations

Settings›Basic›Games and graphics

Recommendation

Keep enabled

Do not disable FSO globally. Use a per-game override only for a game with a reproducible issue.

FSO supports the modern presentation path, fast Alt+Tab and overlays. A global block affects all compatible games of the current user.

Globally

Enabled

For one game

Based on A/B result

Raw Input

Not improved

In short

Fullscreen Optimizations let Windows display a game as fullscreen while preserving the advantages of the modern flip model, faster switching between windows and compatibility with overlays. Disabling FSO does not turn any game into a faster Fullscreen Exclusive and does not improve Raw Input by itself.

In BoosterX measurements, the Raw Input structure did not change between FSO and FSE. An earlier series of physical measurements in Valorant also showed no advantage of FSE in average click-to-photon latency. In individual games, output and frame pacing may differ. Therefore, disabling FSO for one game can help fix a degradation that has appeared in it.

Global registry change

The global FSO setting in BoosterX is experimental and is shown only after enabling the corresponding display mode in the application settings. The exact registry changes for it are not published in this knowledge base. To test one game, it is safer to change FSO only in its profile.

When to disable for a specific game

• reproducible frametime spikes appeared only with FSO enabled;
• Alt+Tab, HDR, VRR, capture or overlay is broken;
• several identical runs show an improvement without new issues.

How to change and revert

For the global state, open in BoosterX “Optimization” → “Basic” → “Games and graphics” → “Global Fullscreen Optimizations (FSO)” and move the toggle to the “Off” position: BoosterX will apply the standard Windows state with FSO enabled. After the change, click “Apply” at the bottom of the page; with “Instant apply” enabled, a separate click is not required. Turning the toggle on globally disables FSO — use it only after testing a specific game using the section below.

To test disabling for only one game, open ProcessX → “Application profiles”, select the game’s profile and in the “Process settings” block enable “Disable fullscreen optimizations (FSO)”. Fully restart the game. To revert, turn off this setting in the same profile.

Sources and scope of verification

• Microsoft DirectX: Demystifying Fullscreen Optimizations.
• Microsoft: For best performance, use DXGI flip model.
• Study of FSO, FSE and CS2.

The recommendation applies to the global toggle. Issues of individual games must be tested separately.

Last verified: 2026-08-26.