I have 1 stick on a usb 2.0 hub on one desktop, and I have 3 more on another desktop.  Of those 3, 2 are in a usb 3.0 port and one is on a Y-cable.  All 4 of my sticks have at least 1 amp available on the their ports, so I run them all at 262.5mhz.

I have a usb fan below and out of the picture that blows up on the heat sinks.