When I received these cables I was amazed. I have the fastest transfer speeds ever. I went around the house, found all the USB3 cables I had and removed them. If you connect another cable, adapter splitter, extension cord, or anything else to this cable, your speed will instantly drop from 350Mbps to 38Mbps when using an external M.2 NVME drive or something fast. My old cables used to piss me off and I didn't know what was wrong. Now I have solved the problem. I came back and ordered 5 of these. The longer the cable, the more it slows down the speed.