New
#21
The 54Mb/s rating of the wireless side of the router is only for wireless. The ethernet speeds you should expect would be 10Mb/s, (Very Old), 100Mb/s, (old), or 1Gb/s ("New") so it should be possible to achieve throughput in excess of 50Mb/s with your existing kit. Of course this assumes that you do have 100Mb/s ports on the router, and on the computers, which would be expected (applies to one computer ethernet connected to the router, shared access will reduce the actual bandwidth of all devices).
One thing you have to be aware of is that very few ISPs serve the "headline" bandwidth they quote - some can say Up TO 100Mb/s and it only Ever get's Up To 50 50Mb/s especially at busy times
Most modern cable / fiber modems also has a built in WiFi Router.
So my question is: Have you read the specs of your new modem? It may have a built in WiFi Router.
My ISP gave me a Arris cable modem that also had a built in a AC WiFi Router. It gave me so many problems that I asked for a replacement. They gave me a Humax cable modem that also had a built in a N WiFi Router (2.4 and 5GHz).
I agree with those who said that you don't need a AC WiFi. They are much more expensive.
If your ISP cable / fiber modem don't have a built in WiFi Router, I would buy a class N (300Mbps).
I have and recommend TP-Link. Never had problem with their products, they work well, cost less and have at least 3 years warranty.
Best Wireless Routers 2018 - Best Picks | PCMag.com
Wi-Fi Routers | TP-Link
I used to have a modem/router that I rented from my ISP. I then found that they had a modem that they would sell me for $25, allowing me to use my own router. I went with purchasing the $25 modem from them, because I already had a good Netgear N300 router. So not only am I no longer paying $8 per month to rent the modem/router, but also I now have full control over the router. I didn't have full control over the rental modem/router - there were areas in the admin screen that I couldn't get to.