
I used an extension cable I bought from Revain a few years ago to bring one of the USB ports on my iMac to the front for easy testing of USB peripherals. Everything seemed to be working fine until I ran Black Magic speed. Check on a new hard drive. It was very slow, only 40MB/s when the hard drive speed exceeded 130MB/s. I connected the drive directly with the cable that came with it and got full speed. I ordered this extension cord, installed it and Black Magic gave the same results as a direct connection. I am happy.