What is V30/V60/V90 (Video Speed)？

These are Video Speed Class ratings for SD cards, indicating minimum sustained write speeds of 30MB/s, 60MB/s, and 90MB/s respectively. Higher ratings support more demanding video recording formats.

Simply Put:

Think of V30, V60, and V90 as different-sized water pipes. V30 is a thin pipe, good for regular video. V60 is thicker for HD, and V90 is a fire hose for 4K or 8K video, providing steady and fast water flow so nothing gets stuck.