This model uses 48% of the usb controller bandwidth. Also 10-20% are system reserved. I solved this issue by inserting each camera into usb ports from separate controllers. Worked like a charm. If the motherboard has too few or low-speed usb controllers one should install an expansion (pci /pciExpress) controller.
To see each controller's bandwidth go to Computer Management -> Universal Serial Bus controllers and right click on one (or more) of the displayed controllers, click on the Advanced tab and one can see bandwidth-consuming devices.