Hot on the heels of AT&T changing its tiered data plans once again, reports have surfaced regarding data throttling on unlimited plans. Although the unlimited option has been discontinued, some iPhone users are grandfathered into the plans and continue to enjoy no monthly limits on usage.
Only catch is that AT&T will start throttling data speeds when a threshold is reached, typically when a customer enters the top five percent of data usage. According to MacRumors this threshold has decreased significantly and now includes subscribers who have reached just 2GB of usage. This number is even lower than the 3GB tiered data plan costing $30 per month that was recently announced.
Previous reports pointed to a threshold of 10-12GB before AT&T started to throttle speeds. Another change appears to be that the company is using some kind of geographic metric to determine who's going over the limit. The customer who reported throttling at 2.1GB was told by AT&T representatives that this number was above the 5% throttling limit for their region. It's not clear what defines a specific region or how the top 5% is calculated by AT&T.
Many users are hitting 2GB and more without being throttled by AT&T, which means the numbers calculated in their region are different. The fact that a user can be throttled for hitting a data usage limit below the current tiered data plans has made readers question whether or not AT&T is just trying to encourage long-time unlimited iPhone users to switch to tiered plans. Sprint currently advertises themselves as the last truly unlimited, no-throttle iPhone data plan remaining in the US.