Ok so I've noticed something here "The games I generally have seen this on are Planetside 2 and BF1. Some games like R6 Siege I can run on max settings without lag." So that differs a little from the question asked initially in this thread.. If I got it right, you are only facing drops in some games but others you run maxed out? I thought you were facing this in every game.
Now regarding the results -
1 - BF1 I can relate myself I have similar specs I5 4690K but a GTX 1080 and I still get frame drops... actually there's nothing much you can do about BF1. Unfortunately the game is heavy on CPU for real.. I get almost 100% of CPU usage all the time, and everytime a explosion happens or there's too much stuff going on around It just drops from like 80 to 50 or 112 to 60 and so on... it seems that since the new DICE's updates have messed the game performance way too much for me and so for the others.. have seem a lot of people complaining about the game performance lately with high CPU usage and FPS Drop issues in most of the maps, I know we shouldn't be having such issues with these specs but it's a game problem not hardware..
You can do this if you feel like it --
1 - Open Windows notepad.
2 - Type RenderDevice.RenderAheadLimit 2
3 - Close and Save the file with the name "user.cfg"
4 - Paste the file in "C:\YourUser\Origin\Games\Battlefield 1
This basically decreases a little the High CPU Usage ingame, it worked for me.. you should try and tell me how it goes. Everytime you start the game it will automatically load this cfg. file, if you don't want to use it anymore just delete it.
As for PlanetSide 2 I can't really help since I don't play it... but both are games with very Big Maps, Intensive Battles with lots of players and so many things going around.
There are any other games that you might be facing these issues?