Question Sudden major fps drop in brand new gaming build

May 9, 2020
Hi, I just built a gaming pc for my friend with mostly used parts. The build is an I5-3570 processor, 8gb ram, RX 580 Graphics card, 240gb ssd, 1tb hard drive. The computer was running fine for him at first. He was running rainbow six siege at around 130 fps for about 5 day’s but now all of sudden he was playing today and the frames just randomly dropped down to 40-50 and he’s lagging super hard. It’s not his WiFi because he tried running the game in offline mode and he’s still getting terrible frames. We checked his temperatures and his cpu and gpu are under 50 degrees Celsius so it’s not overheating. We checked his usage and his components are not under full load. Does anyone know what the issue could be. Could the graphics card or ram be failing since I bought them used? Could it be a bad driver that needs to be updated for his graphics card? I don’t think it’s the storage cuz the ssd is brand new and the game is on that. And it’s not just that game itself cuz he also tried running call of duty and that was frame dropping too.