In real-life use--copying compressed files to and from the card--it clocks in at barely over half the advertised speeds: about 16MB/s read and about 7.5MB/s write, as averaged between testing on several SD slots (some USB-connected, some PCIe-connected) on several computers, plus a just-released smartphone. Very unimpressed by the &#34;up to&#34; marketing of SD card vendors and makers.The actual raw size is also about 59.5GB, which I find fascinating for a flash device, which is only ever manufactured with powers-of-two components. (1KB = 1,024B)