VPN Speeds very slow on Nighthawk AX5 RAX29 Router

Netgear uses an OpenVPN server in the router to allow for remote access to the LAN, though due to the newer encryption requirements, and current implementations of the OpenVPN server using only a single core of the CPU, they tend to have lower read and write speeds. While there are ways to improve the performance a bit, such as using the wireguard protocol which has less CPU overhead, so far the implementations on many routers have not really switched to it yet.

The 3 core 1.5GHz CPU in the RAX29, a client connected to the VPN server will often do around 20-25Mbps download, and uploads to the router will be faster since the router can decrypt the traffic faster than it can encrypt it.

If you want to go for closer to gigabit speeds over the OpenVPN server, you are looking at more of a dedicated home server, where in those cases, you can focus on getting the highest clock speed modern CPU (no need to focus on a large number of cores since even on X86, the OpenVPN server will still use only a single core/ thread.

PS, if you did a home NAS build running something like trueNAS scale, you can also enable its built in OpenVPN server. Then for max performance, if using an AMD CPU, you can use PBO and see if the +200 setting is stable for you, and get an extra speed increase. You can even do this with stock cooling if you keep the overall power limit within the range of what the stock cooler can handle, since it you will still get the full PBO benefit for a single thread workload anyway.