On my HTPC I have two external USB harddrives. Up until recently I've run them on the motherboard USB 2.0 ports and they've been working just fine. Slow, but fine. So, to speed things up I went out and got a PCIe USB 3.0 card with two ports and connected both drives to them. To begin with everything was great and the speed increase was awesome. Problem is, one of the drives gets somehow disconnected after a while, this never happened when I had them connected to the USB 2 ports on the motherboard. This kinda baffles me and I would like suggestions as to what's causing this.