USB 3 + USB 2 vs. USB 3 hub

My laptop has a USB 3 port and a USB 2 port. I want to transfer RAW iamges via a USB 3 CF card reader to portable external HDD with USB 3. I currently plug the card reader into the USB 3 and the external drive into the USB 2. QUESTION: Would the transfer actually be faster if I had a USB 3.0 hub and connected both the card reader and the drive to that?

I don't have a USB 3.0 hub, but am considering this if it speeds transfer.

USB 3.0 has 10x the bandwidth of USB 2.0 so it has plenty of capacity to handle a memory card and a hard drive, neither of which are terribly fast, but are likely faster than USB 2.0. How fast are you memory cards rated for?

judging by the huge speed difference between USB2 and USB3, I'd say you should get some speed improvement. However, I don't know for sure if there are no other variables such as collisions (like packet collisions in ethernet hubs) that play a role in slowing down your transfer speed. I'm not even sure if there's such thing as packet collisions in USB hubs.

mike_d wrote in post #16739277
USB 3.0 has 10x the bandwidth of USB 2.0 so it has plenty of capacity to handle a memory card and a hard drive, neither of which are terribly fast, but are likely faster than USB 2.0. How fast are you memory cards rated for?

My newer cards are fast. I have the Lexar 1000x which claim write speeds of 95 MB sec. My Sandisk claim 60MB/sec. ... and then I have some older ones more in the 30 mb/sec.

USB 2.0 will limit a device to about 35MB/sec for sequential transfers of large files. A typical hard drive will do about 100MB/sec on such transfers. Moving the hard drive to USB 3.0 should get you some speed increase.

USB isn't bi-directional, so the one 3.0 connection will have to multiplex between reading from the CF and writing to the HD. Still, USB3 is ~14x faster than USB 2. Even at half speed or a little worse, you should see a nice speed increase.

Thanks guys. help like this is why I love this site!

My USB 3.0 hub arrived today. Quick test transferring 27 Gb of photos on a Lexar 32GB 1000x CF card from the Sandisk 3.0 card reader in a 3.0 USB on computer to a 3.0 HDD on a USB 2.0 port took 2 min. 4 sec. Using the 3.0 hub on the computer's one USB 3.0 port and transferring the same files from the card reader to the HDD took 30 seconds. YEP, 4x faster. Not bad.

Nice. I was expecting a speed bump, but not that much.

Heya,

USB3 really does make an impact. I do a lot of large file transfers and USB3 has made that such a better experience as before I was just using networks as they were just faster than USB2. If all your interfacing is true USB3, you will enjoy the speed.

Very best,