I want to play around with creating my own router, and upgrading my home network to 2.5g speeds. I think going to get one of the mini pcs commonly bought from Aliexpress with 4 or 6 2.5g ports and install pfsense. Before I pull the trigger, I have some old hardware lying around that I would like to test the software side of first. I have a laptop motherboard which has a WLAN M.2 port available to use. I was thinking about buying a M.2 WiFi A.E Key A+E To PCI-e 4x x4 Riser Extender Adapter Card and then a Dual 2.5g NIC.

What I'm wondering is what speed will the A+E M.2 port max out at? I'm assuming the M.2 A+E slot would be below the bandwidth of fully saturated dual 2.5gb NIC, but by how much?