MUX Switch (Advanced Optimus / GPU Multiplexer)

A hardware MUX (multiplexer) switch allows the display to be directly driven by the discrete GPU, bypassing the integrated GPU compositing layer. Without a MUX switch, frames rendered by the dGPU must route through the Intel or AMD iGPU over an internal PCIe or display mux link before reaching the panel, introducing 10–20% additional latency (frame composition overhead). With a MUX switch enabled, the dGPU outputs directly to the display controller, reducing input lag in games. Found in most gaming laptops from 2022+: ASUS ROG (Advanced MUX), Lenovo Legion (Hybrid Mode toggle), MSI (Discrete Mode), Razer Blade 15/16/18, Alienware m-series.