You appear to only have 2 USB 3.0 ports on the back under the Ethernet connector. I am looking at a revision 1.0 board so you may have a newer revision. All others appear to be 2.0/1.1 ports. You might double check the internal connections to the front ports to make sure they are correct. H81M-D3H
But to be clear, without the Headset being plugged into the front ports, the lag still happened on the back ports for the mouse and keyboard? Sound drivers can also be a problem for some systems as well as devices such as headsets.
Edit: The system also appears to have the charging port option. Is that turned on or have you installed any software for it?
Um I'm guessing this is the port that the SATA cable is plugged into on my Motherboard? If so here is a picture of what it looks like and also a screenshot of my SSD's software homepage Imgur: The most awesome images on the Internet. (Is posting that serial number a bad idea? haha)