Albert: To get sustained 4K-capable bandwidth in the house, about 6 months ago I moved to the then-latest Netgear mega router the AC3200 Nighthawk X6 (Product ID R8000); it's Tri-Band has 6 separate antennae, beam-forming, etc... so you can split out things like laptops, phones, tablets, TVs & BluRay players (both that require WiFI and have embedded apps like Netflix, VUDU, etc...) onto the array of 2.5GB and 5 GHx channels for a total of 3.2 Gbps throughput across all used channels , that suit them best and keep slower speed devices from mucking up throughput for other higher speed devices at high-use periods of the day.
Further, for larger homes, or where the incoming cable modem is upstairs in an office (with the WiFi base router) and other devices elsewhere in the house, including TV and BluRay, other computers, etc...are on another floor and/or you need coverage on back patios, etc....I found adding the sister product, the Netgear AC1900 Nighthawk X7 (Product ID R7000) to extend both 2.5 Ghz and 5 Ghz channels to be ideal.
They appear to have bettered the X6 already with the R8500 AC5300 Nighthawk X8 that provides up to 5.3 Ghz total bandwidth and has a few more nifty features like explicit beam-forming, auto load-balancing (of 5 Ghz channels), etc.....
With the X6 and the Range Extender, I have no issue here with multiple laptops in use in the house, 2 Android phones (1 S5 and 1 S6) that do a healthy amount of email pulls, web access, etc...all the time and 4K UHD streaming via Netflix on my Samsung LED TV that remains dependable.
Questions....ping me on In-mail.