FFXIV Causing Input lag in other windows

I always have more than one window open. While waiting for dungeon queues, I like to browse the internet, or have another game running the background that I can tab over to and play a little of while I'm waiting. My computer can more than handle this and always has in the past.

Recently, though, I restarted my computer and while FFXIV is running, nearly every other program running, be it another game, Firefox browser, etc. when I move my mouse or sometimes when I type, the program in the forefront lags to unplayability. An example; I play another game with FFXIV doing nothing in the background, my character just standing in town, I can move my character in this other game forward with the keyboard with ZERO lag, I try to move my mouse to adjust the camera, framerate drops to 0-5.

I have checked my drivers, all are up to date. I have attempted using another keyboard and mouse, same problem. And as I said, this problem only exists when having FFXIV running. I have tried opening two different games and they run fine without this problem.