A few weeks after flipping the switch on its first next-generation DOCSIS 3.1 modem — which can deliver speeds faster than Google Fiber over existing cable lines — Comcast is detailing plans on which markets will be the first to get access to the service.

In a new blog post, Comcast says it will bring DOCSIS 3.1 first to Atlanta and Nashville. Residential and commercial customers will begin to gain access to the faster service in the first of the year.

During the back half of 2016, Comcast customers in Chicago, Detroit, and Miami will start seeing DOCSIS 3.1 become available.

Even though Comcast’s home city of Philadelphia was the site of its first 3.1 test, the company confirms to Consumerist that Philadelphia-area customers will still have to wait for the faster service to arrive at some point in the future.

While the new tech uses existing cable lines — meaning Comcast doesn’t need to spend billions running an entirely new network — customers will need to get new modems in order to actually take advantage of the faster speeds. These modems are not commercially available yet, so we don’t yet know what they will cost. One estimate predicts the new modems will be upwards of 50% more expensive than their current counterparts.

The rollout of DOCSIS 3.1 service comes shortly after Comcast introduced its new fiberoptic broadband offering, Gigabit Pro. That service, which offers speeds up to twice as fast as Google Fiber, is also incredibly expensive ($300/month, plus up to $1,000 for installation and activation).

Comcast hasn’t yet announced pricing for 3.1 service, but the company tells Multichannel News that it expects it will cost less than Gigabit Pro.

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