Need some help with a perplexing issue in SIOC

[737NUT]

When running SIOC, my USB expansion stops responding after a 1-5min delay. It shows up in the box in SIOC but nothing happens when i flip switch. No led indication on board or in iocp console. If i test the card through controlador program, it functions fine for over an hour. Also, this is intermettent, sometimes all works fine for several hours. Very strange but i have narrowed it down to SIOC stops communicating with the usb expansion and locks the card up. If unplug usb connector and reconnect, all is ok sometimes and others it will stop responding after a min or two. Again, it works perfect through controlador test program.

thanks,
Rob

[CanberraACT]

Only time I had a problem like that was when I had something plugged into USB sockets on the front of an older PC. Turned out they were original USB1 ports and the item was expecting to be plugged into USB2 ports (which I had at the back of the machine). Things would work OK for a short time and then stop talking.