In Firecapture upper left where gain, exposure, gamma, are there is a tab "more".
Click it to change the traffic setting.
Thanks, I finally found the USBTraffic setting and reduced it to 40, but it made no difference. The computer is a Windows Surface 2, not what you would call powerful. It has only one USB port so I am using an external, powered USB hub. I wonder if the problem is somwehere in that mix?