I know this is already sounding like a pretty generic post about somebody saying "Omg my Minecraft is lagging *smashes keyboard*." But hear me out. I've played Minecraft for over a year now, and I never lag. Recently, I tried to record using recording software. It started lagging, so I ended the video really quickly and I thought it was the software. (I used this software a couple of times, and it was completely fine.) Now every time I go to Minecraft, I get massive lag, and Minecraft looks like it limits itself to eight frames per second. Sometimes I would get over two hundred, but right when I start moving my mouse, regardless if I'm moving along with it, it would lag back to eight frames per second. I checked the settings, turned everything down to the lowest graphics, made my frame rate go to unlimited, everything. I've checked if anyone else has ever had this problem. I found something similar to what I needed, and the person on the forum post had said that he had fixed it from the guy above him. I went to see if it worked for me, and it did!
Yet nope. A day afterwards, it started lagging again. I checked my stuff in task manager, and it looks fine.