According to a review posted by Macworld, “Apple Arcade games are amazing on the Apple TV 4K—provided, that is, you can get them to run properly. Frogger in Toy Town has frame rates so low in the opening cutscene that it sometimes resembles stop-animation. I couldn’t even get The Pinball Wizard to run past the initial story cutscene, and so I had to content myself with watching the loading animation spin for several minutes before I finally gave up.”
However, the review also notes that those are extreme examples and that for most games, they run fine with the occasional frame drop. To be fair, Apple Arcade is still a relatively new service and as expected, there will be some hiccups. If you do run into issues with Apple Arcade like framerate drops, know that you’re not alone.
We expect that this is more of an optimization issue rather than a hardware issue, so hopefully future updates will see games run more smoothly on devices like the Apple TV. In the meantime, it seems that there are no issues on the iPhone or iPad.