Question Occasional frame stutter in games


Mar 22, 2016
I've been having a weird frame stutter issue in games. In League of Legends I will be at 144 frames with vsync on, and seemingly randomly my frames will drop and I get this weird laggy stutter for a few seconds and it goes away. Without vsync I get up to 300 frames but I don't like the screen tearing so I keep it enabled. I have however tested without vsync on, and I still experience this. Very very rarely it will be get worse where it basically freezes for less than a second and quickly goes back to smooth, but thats only happened maybe 3-4 times total in the past few months.
My specs are:
VG248 monitor
Ultra Durable z390 gigabyte motherboard
i5-9600k cpu
gigabyte 3070 gpu
evga 600W psu
I've ran multiple temperature tests and benchmarks, everything is fine heat wise, and benchmarks are performing fantastically with the 3070 being used fully. I did overclock my cpu very slightly from 4.6 to 4.8 but I changed it back in bios to see if that was causing issues and it wasnt. Everything is basically brand new.
When I'm in game my gpu is around 12% max and cpu maxes out at 80%. I've tried going through background processes and checking stuff with Riot Support but after a week of talking with them nothing is working. I am using a Display Port cable that I got from another monitor which was 85 hz. I just recently realized this and was also wondering if that could be causing issues, but I'm not sure if display port cables can cause issues like that. Another thing is my HDD is about 90% full and my SSD is around 80%, but I also dont know if being low on storage could be causing it or if something is cluttered or corrupt. Everything is updated, I'm on windows 10 and nvidia driver version 497.29. I just have no idea what more to look at I'm basically stumped with this problem lol... Thank you in advance for any help.