Windows Fullscreen Optimization: Should You Disable It? is a built-in feature designed to give gamers the best of both worlds: the performance of Fullscreen Exclusive (FSE) mode and the convenience of Borderless Windowed mode. While it generally improves the gaming experience by allowing faster alt-tabbing and overlay support, some users find it causes stuttering or input lag in certain titles.
For advanced users, FSO behavior can be tweaked via the Registry, though this is risky and generally unnecessary for average users. Some third-party tools (like "DWM Optimizer" scripts) attempt to strip the DWM down to Windows 7-style logic, but these often break HDR and multi-monitor setups. windows fullscreen optimization disable