4K needs roughly 15-25 Mbps sustained, which works out to about 7 GB per hour of viewing. 1080p needs 5-8 Mbps, closer to 3 GB per hour. Your plan's advertised top speed isn't the number that matters here. What matters is what a real speed test shows you sustaining over a few minutes, since that's the figure a live stream actually has to keep up with, segment after segment, for as long as you're watching. A connection that hits 100 Mbps on a quick burst test can still fall well short of 4K's requirement once you factor in other devices on the same network, background downloads, or a router that struggles under sustained load rather than a short spike.

A live stream arrives as a sequence of roughly 6-second segments rather than one continuous feed. If your connection can't keep pace with even one of those segments, you see a stall the length of that gap, which is why buffering often shows up in short, repeated bursts rather than one long freeze that ends the session entirely. This also explains why buffering can come and go within the same channel over just a few minutes: it's tracking small, real-time dips in what your connection can sustain, not a single fixed fault that either exists or doesn't. Understanding this mechanism is what separates a useful fix from guessing at router settings that don't touch segment delivery at all.

HEVC-encoded streams need about half the bitrate of H.264 for the same picture quality, so a device or app using HEVC gives you real headroom on a connection that's otherwise marginal for a given resolution. This is one reason two people on what looks like the same advertised internet speed can have very different buffering experiences watching the identical channel, since one device might be decoding an HEVC stream while the other is stuck on H.264 for compatibility reasons. If your device supports HEVC playback and your buffering is borderline, that's a real, checkable variable worth confirming rather than assuming your connection alone is the whole story.

If a lower resolution on the same channel still buffers, and the same thing happens on a second device on a different network entirely, that points to a server-side capacity limit on the feed itself rather than anything local to you. No local setting reaches that layer, no matter how carefully you adjust your buffer, your DNS, or your resolution. This is why a provider's own uptime figure matters when you're choosing who to watch through: a specific number like 99.99 percent tells you how rarely this particular failure should happen across the whole service, not just a promise that it won't.