1)This site unfortunately does not just compare the cpu and gpu against others at STOCK, but all conditions(including OC'ing), which can be very misleading.
FYI, overclocking will not fix things if the games you play can utilize more threads than your cpu has. Mass multiplayers tend to utilize more than 6.
Cpu looks bad, but it actually isn't; it's boosting normally, and background cpu usage was kept low.
2)WD Green 240: dramless SSD and low capacity.
This combination means that it doesn't take much data to put on it before performance drops off a cliff. The lack of a ram cache is not worth their low price.
Monitor disk usage.
3)C drive.
Check drive health. There may be a high number of bad sectors, thus slowing it down, so prepare for the possibility that you will need to back up your data and get a replacement drive.
Link to Crystal Disk Info:
https://crystalmark.info/en/ (the blue bar right below Quick Downloads.
4)The group of mixed ram.
It's probably not related to game performance, but if you've been experiencing any blue screen crashes, this would be the likely cause.
Another possibility is that it can slowly and stealthily corrupt your OS over time, if those sticks aren't actually compatible with one another.