The SD Association has introduced the SD Express 9.1 specification, paving the way for SD cards with significantly faster transfer speeds. The specification incorporates PCIe 4.0 and NVMe architectures, potentially doubling maximum speeds to 2GB/s. It also introduces a new labeling system to indicate speed classes, helping users choose the right card for their devices. The speed classes range from 150MB/s to 600MB/s.
Additionally, the specification brings features like multi-stream support, allowing users to record and transfer multiple feeds onto an SD card, and power and thermal management to prevent overheating issues. However, it may take some time for SD cards and readers supporting these new speeds to enter the market. Future specifications are expected to support transfer speeds up to 4GB/s.