ROBLOX runs badly, despite a good PC?

Sometimes runs smoothly, but there are sometimes enormous FPS drops. Other games like Battlefield, Apex, Fortnite run smoothly on max settings. Why is that?

System:

Graphics card: RX 580 8GB

Processor: AMD Ryzen 5 1600

RAM: 8GB

The game is from 2005 and therefore only supports 1 thread. The first Ryzen generation had not so good single-core performance and therefore the drops are normal. Either overclock the CPU or upgrade to the Ryzen 5 3600.