Question Severe fps drops and general lag after doing some overclocking

Nov 15, 2020
(TLDR at the end)
First of all, I have a EVGA gtx 1060gb SC edition, a Ryzen 5 1600 and 16gb of 2666mhz RAM (2x8).
I've had this setup for 3 years now, and I've never tried to OC before today. I wanted to see what all this "overclocking" fuss was all about so I did several tests using Assassin's creed Odyssey as a benchmark.

- Firstly, I attempted to get my RAM up to 2666mhz (was 2133mhz) using XMP profiles in the BIOS.
Result : 10 to 20 fps drop in AC Odyssey.

- So i set my RAM back to default, and then tried to boost my 3.2ghz CPU up to 3.6ghz (game boost mode for the R5 1600).
Result : absolutely no changes whatsoever.

- I then launched EVGA Precision X tool and activated the "K boost" mode to pump up my GPU from 1607mhz to about 1980mhz.
Result : 5 fps more in AC Odyssey, gpu temperature went up to 72 degrees.

So while having my CPU and GPU both on "boost' modes, i fired up World of Warships and had a whopping 25 fps average instead of the usual 60+ fps.
After turning off both K boost (GPU) and game boost (CPU), I restarted my pc and went back to play some World of Warships and, surprise surprise, my fps is still extremely low at around 20 to 27 fps. I tried other games, like on Battlefield 1, and it was the same issue. I usually have more than 60 fps and now i'm between 25 to 45 fps max.
I tried going on twitch to watch a crowded livestream and everything was laggy, the video and the chat. My mouse and keyboard imputs had a slight delay and everything seemed to go very slowly.
I reinstalled my gpu drivers, deleted EVGA Precison X tool and restarted the pc again, but nothing works.
Does anyone here know a trick or 2 to solve this problem ? Many thanks in advance.

TLDR : i tried doing some OC, did'nt make much a difference, but when i set everything back to default I now have a very slow pc and severe fps drops in all games. help