Simply put, T-Mobile has a policy in place where, if you’re in the top 3% of data users, your access to data is prioritized below other people’s. There’s a practice in place which flags these users on the system. It’s given a brief mention in the “About T-Mobile” page under the consumer tab:
Now, this is worked out on a month-by-month basis. Customers that are flagged for using more data than 97% of customers in a given month will be reset at the beginning of their next bill cycle. Sadly, there’s no specific figure in GBs downloaded to go by. Nothing anywhere that says that if you hit 20GB, you get throttled. It doesn’t work that way. It’s based on percentages.
The answer to that is “probably not”. First off, it’s very unlikely that you’re in the top 3% of data users unless you’re going crazy downloading tons of content over LTE. Secondly, it depends very much on what the network conditions are like in your area and how many people are using the same cell tower at once. If you’re a high user in an area where the network is unlikely to feel the effects of congestion, you won’t notice much difference, if any at all.
T-Mobile notes in its communication to staff that the “overwhelming majority of customers that have their data requests de-prioritized are in places of normal network contention. This means that while they may see their speeds drop a bit and will be slower than other folks on that tower, they are still getting really strong data speeds (and are not likely to call in to Care).”
Network contention is where multiple users are trying to access the same tower at the same time. Congestion is when there are so many that services/speeds are impacted.
In most cases, during normal contention, the difference in speed should be small enough that customers won’t even notice the difference. As an example, once customer might be getting 20Mbps download speeds while the de-prioritized next is getting 10-12Mbps.
During these busy times, if you’re in that 3% of high users, your access to the network is seen as less of a priority that those who use much less data.
Congestion doesn’t happen everywhere and only affects a small number of towers. But these are the areas where customers are more than likely going to feel the pinch of drastically reduced speeds if they have been de-prioritized. In many cases, in these heavily congested areas, speeds could be around or below 1Mbps.
De-prioritized customers will – more than likely – see their speeds increase during the evenings and weekends when the networks aren’t as busy. The traffic alleviating measures only really kick in during busy times and on busy sites.
T-Mobile has reiterated a number of times that it doesn’t “throttle” customers. And, as much as this might feel like being throttled to the high users in congested areas, it isn’t. In fact, in T-Mobile’s systems, customer accounts which have been de-prioritized will have a flagged notice which makes it clear that it isn’t a throttle, and that they are being bumped down the network access priority list for using a lot of data. Unlike throttling, which effects a customer regardless of how busy or quiet the local network is. This is an effort to stop congestion from having a serious impact on the network performance rather than being a blanket targeting of every single high data user.
Brandon, the original poster on Reddit stated later on that he spoke to someone from John Legere’s office who reiterated as much to him.
Long story short: Don’t worry about it unless you’re constantly watching movies over LTE and you live in a busy area.