Why does dxtory drop a lot of frames?

So my PC specs are gtx 760, and i7-4770k, and 8GB ram I've only had this pc for 4 months and everything has been fine. I get about 200-800FPS in minecraft max settings and now all of sudden when I try to record with dxtory when I've always used and no problems all of sudden I drop so many frames when I start recording, it will go from 150 to 40FPS for no reason. Even fraps does the same thing, I'm assuming it's something wrong inside my computer. Any help would be appreciated!

Have you tried Bandicam? It's pretty lightweight. If you still lag when using Bandicam then something is surely wrong.

It could be some bloatware or something you've installed recently - be sure nothing else is running.
Windows is horrible… A fresh install may help if you've exhausted all other options.