@NYC_rapp113 

Hi There

Yes as congested as New York is that is like the cause.  2.4GHz can at most achieve 100 Mbps.  The more interference and congestion from other 2.4GHz devices or networks can diminish that as well as with the many brick buildings and other devices such as Microwaves that operate on this spectrum speeds can easily diminish.  Becasue when Smart Connect is enabled the router is doing your networking for you it would be a good idea to disable it and manually assign your laptop to the 5GHz connection.  Let us know what the speeds are from there.

@NYC_rapp113 

Two things to consider here.

1) Are you using the same SSID and P/W as before for wireless?

2) Have you powered off the Arris TM1602AP2 before connecting the new router? This should be done always.

Also, how have you determined the wireless is connecting to 2.4Ghz as both the 2.4Ghz and 5Ghz bands are using the same SSID under Smart Connect.

As for wireless speeds, besides congestion/interference, the 802.11 device rating comes into play, especially when one wants to get higher speeds. Devices have a few numbers, Connect Speed, Theoretical Speed, and Actual speed. Even an N Speed device might not reach 300Mbps, but more like 150Mbps. A good web page that explains all this, though somewhat technical is https://www.duckware.com/tech/wifi-in-the-us.html.

If you want to get 300Mbps (or 400Mbps) you'll need AC speed devices, not N speed.

Your router has a Speed Test, what does it show?

There could be other settings on the router that needs to be altered or turned on/off as well that could effect the speed.