I have a non-wireless modem-router (Ovislink OV604V) with some devices plugged into the LAN ports there. From one of those LAN ports, I have an ethernet cable running across my home, connected to the LAN port on a router in another room. This router acts as the wireless access point, as well as having my PC and consoles plugged into it. It acts as a network switch. The modem is doing the routing and DHCP.
I'm looking at upgrading my router because it's quite old and doesn't do 5GHz wifi (it also cuts out sometimes). I have my eye on a gigabit router. I understand that this won't upgrade my internet connection, but since the router isn't actually doing the routing and is only an access point/switch for my modem network, will two devices, both plugged into the gigabit router, be able to achieve gigabit speeds between them?
Example 1: If my PC is plugged into the gigabit router, and a NAS is plugged into that same router, would a file transfer between the NAS and the PC be able to achieve the full potential speed, or would it be "passed through" the (aging) modem and be bottlenecked?
Examople 2: Would connecting my phone to the 5GHz network on the router allow it to get a fast connection from Steam link on my PC, without a bottleneck from the router?
The router I'm looking at is D-Link DIR-867. I won't be upgrading the modem soon because my apartment building is going through the process of having fibre installed so I'm waiting until that goes through before modem shopping or upgrading my service.