It's the i5-4200 8GB RAM 64GB SSD version of this one:
https://www.aliexpress.com/item/3286...61224c4d0Zilc3
Did a clean install from USB and currently running Untangle 15.0. Performance is fine, my home network isn't very demanding. The kids are still young, so whilst they stream a lot of stuff from the smart TV etc, they're not all simultaneously gaming online, etc etc. Memory usage hasn't gone over 25% and disk is at about 30%. I don't have SSL inspection enabled except on the Kids and IoT policies (to enforce web filters, safe search etc) so CPU usage seems minimal.
Compared to the Cyberoam device I had before, it runs with way more headroom even when things are pretty idle, so I'm hoping it will last me a good while into the future.
Screenshot 2020-05-31 at 15.44.31.png