Ubiquiti EdgeRouter X is a tiny and cheap (around $50) router with a decent amount of memory: 256MB RAM and 256MB flash. The router offers 5 GigE copper ports, and there’s also a model with an additional SFP port. The device is produced since 2014, and it’s still up to date and a good value for money.
On hardware level, the device consists of a Gigabit Ethernet switch, with one GigE port attached to the MIPS CPU and used as a 802.1q trunk. Also inside the enclosure, serial console port is available for easy debugging or manipulating the boot loader.
The router comes with stock Ubuquiti software which is based on Debian Wheezy, so many files are from 2013-2014. OpenVPN package is pre-installed, but only version 2.3 is available. The software offers a nice GUI and SSH access.
OpenWRT provides excellent support for this hardware. The router is able to perform IP routing at more than 400Mbps (I haven’t tested it with back-to-back connection, so I don’t know the limit).
Also with OpenVPN 2.4 that is available in up-to-date OpenWRT packages, the box performs at up to 20Mbps with 256-bit AES encryption, and at about 55Mbps with encryption and authentication disabled.
In default OpenWRT configuration, the switch port 0 is dedicated to WAN link, and ports 1-4 are used as a LAN bridge. The WAN link acts as a DHCP client, and LAN is configured with DHCP service in 192.168.1.0/24 range. The command-line configuration utilities are quite straightforward, and there’s a Web UI as well.