About capacity: 512GB=approximately 462GB-490GB This is calculation difference between manufacturer and our PC, please Google 'Memory card capacity' to get more information. Warm Tips: 1.Our Store offers genuine memory card with 1 year warranty. 2.Please use quaity card reader to verify memory card on PC. 3.Please don't use cheap card reader to test memory card, speed of memory card will be reduced by low quality card reader. 4.Memory card speed is greatly affected by card reader, adapter, USB port etc. Low quality device will slow down card speed. 5.Up to 15MB/s read speed; write speed 10MB/s. Based on internal testing; performance may be lower depending on host device, interface, usage conditions and other factors. 6.If you have any questions about this card, please contact us directly through Amazon. thank you for coming!