Hi,
I bought this motherboard: Asrock J3455M NA, it has an embedded Apollo Lake Celeron, 4 cores, 1.5/2.3Ghz, 10WTDP, supports AES-NI
added
4GB of DDR3 RAM
4 port Intel I350-T4 PCI Express PCI-E
already had the case, the hd and the power supply,
ended up spending around 150GBP for a <10W 4 core (albeit celeron) processor and a quad port intel nic.
My Internet connections are slow, one wifi at 30Mbps/3Mbps and an ADSL at 10Mbps/512Kbps, multiple IPSEC and OPenVPN tunnels terminated on it, cpu never goes over 10%, coming from an old celeron@600Mhz with storage on a CF card the system is pretty fast.
The only issue I had is that it would not boot 2.4.x due to a bug, solved by applying this fix: https://forum.pfsense.org/index.php?topic=139027.msg760012#msg760012
Regards,
Mattia