Q: Slow speeds from new Airport Time Capsule

What modem do you have?

Make and model please from the label.

There are known issues with any of the single port SB series.. and the wan port of the Airport.

Wesley4567 wrote:

 

Motorola MB7420

It is a new one to me but it is a single port modem made by Motorola which also of course originally made all the surfboard series. And I would expect WAN port issues on the apple router with it.

Your choices are replace the cable modem with one known to work well with the airport.. lots of people recommend the zoom models.

Zoom modem.

https://discussions.apple.com/thread/7360161

https://discussions.apple.com/thread/7427491

Or replace the airport as your main router.. a cheap standard Netgear or TP-Link etc. router with at least gigabit ports.. and then bridge the TC to it for use as Wireless Access Point.. WAP.. and switch and Time Machine target. All of which will work fine once the TC is no longer routing.