Suddenly Low FPS

I've been playing BeamNG.drive for about 3 years now and I have been playing on my new gaming pc for about 8 months. I have a 60htz monitor therefore I lock my fps at 60 in all of my games. I always have had a steady 60fps or just under 60 in dense areas, and this is with all the settings maxed out. I've noticed this fps difference since the other day when I cleaned up my PC. I cleaned my trash bin, deleted some random files and folders and I organized my content. I run beam off a 7200 rpm HDD and it has worked well as I mentioned before. For the past two days my fps has been terrible. I was running the Italy map, which I think is slower for most people just because of its extreme detail and size. I got nearly half the fps I usually get...an average of around 35fps, dipping to 32fps in large areas of trees and buildings. My game has NEVER run this slow ever. I immediately got off the Italy map and tried something different. I went to pure grid, and I got 56 fps off pure grid! The game was shaky and stuttering. The performance wasn't smooth at all. I'm not sure at all why this would happen since I cleaned my PC, but my immediate thought was blaming my HDD for some of the slow downs and stuttering. I defragged my HDD and then cleared the cache of my game and nothing has changed. Still buggy and slow. I haven't tested any other games but my PC is performing well doing every other task I need except playing beam. Please help and give me suggestions...and for the love of God please don't tell me to get an SSD because I know I need one but at the moment I just can't afford to replace my HDD with an SDD of the same size. So here are my specs below.

Motherboard: GIGABYTE AB350 Gaming 3
Processor: AMD Ryzen 7 1800x @ 3.7GHz
CPU Cooling: Deepcool Captain 120EX RGB Gamer Storm
RAM: 16GB [8GBx2] GSkill Ripjaws V DDR4
Graphics Card: Nvidia GeForce GTX 1080TI Aorus Xtreme Edition
PSU: 1000W PSU (High Power)​

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UPDATE: I installed a new BIOS Version and now I'm getting the best FPS ever, and better than before. Didn't expect it to make a difference, but I guess when your 5 versions back it could...