Unusual fps stuttering and drops

I really hope that I can find a solution to something that no one anywhere else online has been able to help me with. This is going to be a long thread so here we go.
I have a
-gtx 1080,
-I7 4790 clocked at 3.6ghz ,
-8gb of ddr3 ram,
-msi z97 gaming motherboard,
-HDD for my OS which is a 5400rpm HDD
-HDD for my games, the HDD is 7400rpm.
So usually with almost every game I play with an exception of a few titles I get massive stuttering and fps drops. usually no matter what I do to the game settings. Something that I tested is something else everyone I've talked to can't explain. If I lock my fps to 60fps with vsync I will still get dips into the 50s or lower, however if i unlock the fps and let's say I'm averaging about 80fps it will dip into the 60s or lower. So regardless I get fps dips. I have no idea what could be the cause of this and usually I wouldn't really let something like this bother me but I've spent a lot of money on my pc and I want it to be justified. It's leaving a nasty taste in my mouth about pc gaming and It's becoming a pain more than anything. I want to love my pc and I want to feel like what I put into my pc was money well spent. So far that's just no the case though. I've tried everything from resetting to defraging my HDD. Almost anything software wise I swear I've tried. Something is telling me it has to do with my ram or HDD but I want to know for sure if it's possible before I just go replacing parts and possibly wasting more money. Please someone help, I've tried going to reddit and steam user forums and geforce for help but everyone always has a different solution, a different reason and it always amounts to nothing. Please if you can help me.