The Standard NVM Express Controller driver in Windows is a generic driver that enables your system to communicate with an NVMe (Non-Volatile Memory Express) solid-state drive (SSD). NVMe is a high-performance protocol used by modern SSDs that provides faster read/write speeds compared to older storage interfaces like SATA. The Standard NVM Express Controller driver is used when Windows automatically installs a generic driver for an NVMe SSD, allowing it to function without the need for specific proprietary drivers from the manufacturer.