Hello, I have the 4k fire stick and noticed a lot of buffering which I am not used to. Therefore I ran a speed test on my firestick and my download speed was only 30mbps, this is compared to any other device in the same room which is getting 100+ mbps constantly.
So I'm wondering how am I getting such a decrease in speed with my firestick when other devices in the same room are getting x3 the speed (all devices are connected to Wi-Fi using a 5Ghz connection.)
I recommend checking the network status of your Fire TV stick.
You can access this tool by selecting Settings > Network from the Fire TV menu and pressing Play/Pause .
The tool checks to make sure that your device is connected to your selected network, and that the network has an active Internet connection. Any problems with your connection are described on-screen, with recommended resolution steps.
Check whether the number of junk files is increased or not. The problem may cause because of junk files because the same things happened to me. Then I installed the IOLO system mechanic to clear the junk files. Now the speed of my internet is as fast as previous.