T-Mobile is putting the brakes on high-speed data gobblers.

A company statement revealed that starting Oct. 16, T-Mobile will begin reducing data speeds when a customer exceeds 5GB of data usage in one billing cycle.

T-Mobile is assuring customers that the measure – put into effect to “ensure that all subscribers receive the best Web performance available” – will impact less than 1 percent of data users and that the majority of T-Mobile customers will not be affected by the new policy.

Fortunately, T-Mobile is promising to give subscribers due notice. The company said that customers found to exceed the limit will receive a free text message informing them that their allowance has been reached and data speeds will be reduced from then on (until the next billing cycle).

Of course, T-Mobile customers that have recently upgraded their subscriptions to leverage the company’s new HDSPA network are certain to be miffed by the announcement. Earlier this year, T-Mobile completed upgrading its entire network to 3.5G, aka HDSPA 7.2mbps, surpassing AT&T in terms of network speed.

In fact, in August, a T-Mobile customer filed a class-action lawsuit in California alleging that the carrier markets certain phone plans as providing unlimited data usage, but then caps the bandwidth once the consumer has signed a two-year contract.

However, T-Mobile’s Data Plan Terms backs up its right to throttle. The contract reads: "To provide the best network experience for all of our customers we may temporarily reduce data throughput for a small fraction of customers who use a disproportionate amount of bandwidth. Your data session, plan, or service may be suspended, terminated, or restricted for significant roaming or if you use your service in a way that interferes with our network or ability to provide quality service to other users."