Thank you. For reference I use Windows 7 and an AMD R9 270X graphics card so that might skew the real world results for me. On my old system with a LGA1156 board from Intel I never had DPC or mouse lag problems, then again it did not have USB3. I however have a AMD based ThinkPad with USB3 and have noticed minor audio issues related to USB3 so I use a USB2 port instead. On my current board I have USB3 disabled in BIOS completely for troubleshooting. Could you show the drivers tab in LatencyMon sorted by "Highest execution time" for me? Thanks.
I do have a Logitech USB headset, never had DPC issues like I said with previous system or Thinkpad even while running games at the same time.