MicroSD card speed affects Switch game load times and performance. The Switch requires a UHS-I speed class (minimum 10MB/s write speed), but faster cards (90MB/s+ read speed) reduce load times for large games like 'The Legend of Zelda: Tears of the Kingdom'. Sequential read speed is most important for loading game data—aim for 100MB/s or higher for optimal performance. Write speed matters for saving game data and capturing screenshots/videos—30MB/s+ is ideal. Avoid 'Class 10' cards that aren’t UHS-I, as they’re slower. Recommended fast cards include SanDisk Extreme (160MB/s read), Samsung EVO Select (130MB/s read), and Kingston Canvas React Plus (170MB/s read). Faster cards are worth the investment if you play graphically intensive games or have a large digital library.