AT&T announced a policy change on throttling data speeds for customers with unlimited data plans Thursday. 3G/HSPA+ customers will now be throttled once they reach 3GB of data usage and 4G LTE customers will be throttled when they hit 5GB of data.

Previously, AT&T customers with unlimited data plans noticed download and upload speeds slowed considerably around 1.5GB to 2GB of data use, as its largest regular data tier was 2GB per month for $25. The company recently changed its standard data options to to 300MB for $20 per month and 3GB for $30 per month (the same price as the old unlimited plan). It looks like the unlimited users will benefit with this bump, as much as they can on an unlimited plan that has, well, limitations.

According to a statement given to Ars by AT&T representative Seth Bloom, whether customers are throttled at 3GB or 5GB of data usage depends on the type of smartphone they have (regardless of what network they are using). For instance, customers with a 4G LTE smartphone who only have access to 3G networks can still use up to 5GB of data before throttling kicks in.

"Because spectrum is limited and data usage continues to soar, we manage our network this way to be as fair as possible and so we can provide the best possible mobile broadband experience to everyone," the statement reads. AT&T explained that the new policy's limits and subsequent throttling extend through the billing month; once the billing period rolls over, the caps are reset. The company stated if customers don't want to be throttled, they can switch to a tiered data plan and their data won't be slowed—but then they'll have to pay for overages.