Performance Issues since November

Hi all, I thought this would be worth posting, as I've seen others with similar problems and wanted to share my own experience. I bought a new gaming rig about a year ago and played league on it for about 11 months with absolutely no issues. I would have anywhere between 150-300 fps throughout every game with seamless visuals. Recently, around the start of November there was a patch that came out where I started experiencing some serious issues. All of a sudden, I was getting as low as 40-50 fps later into my games (terrible freezing and choppiness) and it was making it really hard to play. My first response was that it must be a problem with my computer. After sending it into repair with the manufacturer, I just recently received it back (took about a month). I downloaded league and my FPS is still having serious issues. What is strange is that the FPS seems to stay above 60 for the most part, but there is this obnoxious stuttering and freezing that makes the game look glitchy, especially when my camera is centered on my Champion. In addition to this, adjusting graphics to very high or very low does not rid the computer of this annoying stutter. I've read a few Riot responses that they have acknowledged this and will continue to work on a fix, but I thought this may help others or Riot themselves.

My PC specs : AMD FX 8350 RX 480 8gb ram

Given that my CPU is a fairly old part and is somewhat dated I feel like it might have something to do with this? when looking at MSI afterburner, league barely even utilizes my GPU. If anyone has any thoughts on what to do or has had a similar experience during November-December let me know! Extremely frustrating....

Going to play Overwatch at 200+ fps seamlessly while I wait for some kind of fix...