There should be a cgminer command to list all devices, and I believe it tells you the bus/port numbers. On my testers the busses enumerate as 0/1 or 0/7 depending on machine, so I run two separate instances of cgminer, one pointed at bus 0, one at bus 1/7, for easier note-taking about which devices are on which hubs during burn-in. We run up to 7 sticks at 400MHz per bus (note the bus usage is equivalent to 5 sticks at 550MHz); any more and we had stability issues like you're seeing. We test on debian linux, which I guarantee will make a more efficient use of the bus than your Windows.
thanks. I used the List all devices command and got this back:
USB list: Failed to open 9
0 total known USB device
how do you point instances to a different Bus? is there a line in the config file for that ?
Yeah the 10 port 120W hub is better than the 7port one I thought you had, but its still only 2.1A per port. I've had no end of trouble testing different hubs and only the Gekkoscience ones work reliably in my experience.
For reference, mine pull 2.7A per port on GekkoScience hub.what do you use to get the power consumption reading per port ?
Processor AMD FX(tm)-6100 Six-Core Processor - 4.12 GHz (24.7GHz total)
Sorry, but this I've never seen! 
You add the frequencies of your CPU cores? That's funny.Is it ?? well, if you prefer 6x 4.12 GHz