Firestick generally ships with less onboard memory than a dedicated smart TV platform, and that gap matters more the longer a session runs. Background processes from the app itself, from the operating system, and from anything else installed quietly build up in the background over hours of use, leaving less room for the player to hold a smooth stream. Closing the app alone doesn't clear this, because much of what's accumulated sits at the system level, not inside the app you just backed out of. A full device restart clears it in a way closing the app never does, which is why it belongs first on any Firestick-specific troubleshooting list, ahead of any buffer or network setting you'd normally try.

Before you blame the Firestick itself, confirm the scope the same way you would on any device. Watch a few different channels and a few different groups. If it's one channel, the fault is with that channel's source feed, not your Firestick at all, no matter how it feels in the moment. If it's one whole group, the issue sits with the backend serving that specific category. Only when buffering shows up across everything you try does the device itself become a real suspect worth investigating further. Skipping this step and jumping straight to a factory reset wastes time on a problem the device was never actually causing in the first place.

Firestick pushes system updates automatically in the background, often without much notice, and app updates land the same way through the store. If buffering appeared in the same window as either kind of update, that timing is a stronger signal than anything about your network or your router. Post-update regressions are a real and recurring pattern, not something rare you happened to run into by chance. Check the app's version number and, where you can, roughly when the Firestick itself last updated. If the two line up, look for a follow-up patch before spending time on buffer settings or DNS changes that were probably never the actual issue causing what you're seeing.