32GB U1 Class 10 speed, Max Read speed to 95MB/s = SDHC
64GB/128GB/256GB U3 Class 10 speed, Max Read speed to 100MB/s = SDXC
About REAL Capacity
16GB = approximately 14GB-15GB
32GB = approximately 28GB-30GB
64GB = approximately 58GB-60GB
128GB = approximately 119GB-120GB
This is calculation difference between manufacturer and your PC, please Google ‘Memory card capacity’ to get more information.
For your reference
Your PC says 1GB = 1.073741824 Billion bytes where Market Defines 1 GB = 1.00 Billion bytes.
How to verify the Capacity and Speed of the memory card?
1). Please use quality USB 3.0 card reader to verify all memory card by H2testw on PC. Real memory card should pass H2testw with no error.
2). Please don’t use cheap card reader to test Micro SD card, speed of Micro SD card will be reduced by low quality card reader.
3). Micro SD memory card speed is greatly affected by card reader and the capacity you choose , USB port etc. Low quality device will 100% slow down card speed,1MB=1000KB.