So, I found an interesting... and potential issue with my ASRock Professional Gaming I7 board. It's hard to know for sure if this was the issue, but it all started when I was playing an FPS, and I noticed that I just wasn't performing well. I checked and rechecked to make sure that my settings were correct on the mouse (DPI options and current setting), in the game (sensitivity multiplier) and in Windows (the cursor speed). Nothing was different from my Skylake build, but to make sure, I copied over my settings for the game.
Later on, I was looking at photos on the web, and I kept noticing that I would skip a photo randomly when clicking on the next button. That seemed a bit weird, but it really stuck out to me when I went to select a file, and all of a sudden the file opened. A that point, I realized that I was getting accidental double clicks when I was most assuredly single clicking. I did a little research, and I found a note from Logitech about another one of their mice stating that if there are issues with unintended double clicks to make sure you're using USB 2 instead of USB 3. So, I moved it from the mouse port to a USB 2 port that I added. The motherboard itself doesn't really have many USB 2 ports, so I had to put in one of those old-fashioned add-ins that goes in the expansion port and just connects to a header. (Although, the plastic shielding on the motherboard did make it not install properly.)
After making the change, I did notice considerable changes in my overall accuracy and the accidental double clicks were gone. I can't remember with 100% certainty which port the mouse used on my old desktop, but the Skylake PC uses a Maximus IX Hero, which has 4 USB 2 ports on the back and I tend to plug in mice and keyboards into USB 2 simply because they don't need the extra speed. To be fair, I can't say that the USB 2 change might have been the only possible reason. I use a Logitech G903, which is a wireless mouse. Logitech gives you an adapter to let you plug in the sensor to the charging cable, but you can also disconnect the sensor and hook the charging cable directly to the mouse for data + charging. I'm pretty sure I charged the mouse and swapped back to wireless at the start of the session where I noticed the weird mouse behavior. Although, that wasn't my first time doing that, and I've done that on the Skylake system too.
So, in short, I would consider avoiding the mouse port on the ASRock Professional Gaming I7 board. It might be problematic, so it's probably more worthwhile to just stick with USB 2.