Hello, as mentioned in the FZ1000 thread below, I am trying to work out if my memory card reader is limiting the speeds on my micro SD cards or not. Bought a camera that came with what looked like a genuine Sandisk Ultra 64GB although it is only Class 10 not U3. However, taking 4k video the camera recorded but sometimes said speed not fast enough and taking a bracketed photo (-0.3, 0, +0.3), all those photos had ghosting like the images were either corrupted in the saving or not saved fast enough. So, after going onto the Bay and buying two fake cards Samsung EVO+ U3 cards which were fake commented on another post in another thread here, I bought a Toshiba Exceria M302 EA which is U3. Having tested both these cards in my USB 3.0 card reader plugged into both a 3.0 and 3.1 port my speeds are still significantly off on both cards. The Toshiba averages around 68MB/s for 16MB>64k reads and then slows down. However, the writes are significantly slower averaging 16MB/s for 16MB>512k then speeding up 20MB/s for 256k>64k before slowing down for the smaller files. The SanDisk Ultra Class 10 in the same reader and ports shows high 34MB/s reads from 16MB>256k fefore slowing to low teens from 16k and lower. The writes are high 14MB/s or low 15MB/s from 16MB>512k. It speeds up to 20MB/s and then 28MB/s 256k>64k before slowing for the smaller files. So, are both of these fake or is it my PC or card reader? The higher read speeds of the Toshiba imply that both reader and PC seem fine as a peak of almost 69MB/s means that a write speed of "minimum 30MB/S" is limited by neither card reader nor PC. Using USB Flash Benchmark (www.usbflashspeed.com) for speed test and FakeFlashtest v1.09 www.rmprepusb.com to test the sectors. TIA NB P.S. If anyone wants, I can include the test outputs (text) in another post assuming it isn't breaking forum rules.