5d Slow Connection

Hi, I have a 5D connected via USB 3 and it has suddenly become slow to respond on the main Dell XPS 8930 that it has been running fine on. This has also happened on the prior computer to this one. I tried different USB hubs and cards with no success as well as different USB cables. When I hook up to my laptop it performs well.

The drobo has plenty of free space.

Any help would be appreciated.

Thanks, Dan