Sonnet makes two USB cards that I'm interested in: Allegro USB 3.0 4-Port and a Pro version which features a separate controller for each port. I saw no mention of how many controllers the standard version has so it could be one or two. I have a USB 3 graphics 4K adapter which I want to set up with a 4K TV as monitor. My question concerns how USB cards will divide the controllers' data transfer max throughput. In the case of the pro card all 4 controllers are completely isolated from one another, which I think might be be ideal for my application. Each controller offers max USB 3 capability. In the case of the regular version I'm guessing that there are two controllers (I have a question in with Sonnet, the maker) and each of the four ports shares a controller with one other port. Am I correct in thinking that if two devices are on the same controller but one of them is idle (e.g. a synced iPhone, a drive which is not doing I/O or a card reader that has completed its transfer), that the active device will have max USB 3 transfer rate? (The relevant hardware can be viewed at OWC in case the USB graphics adapter piqued anyone's interest in cost effective real estate.)