it is an 800 MHz VIA c3 with a Gigabit switch on the inside interface
and 20 Mbs symetric Fios on the outside. both interfaces are 100 Mbs.
I'd done a bit of testing of a VIA EPIA C3 (either a 600 or 800) with
the on-board vr0 and an Intel fxp card, and it seemed to go OK up to ~
8MB/s aka ~65 megabits/sec with a fairly short IPFW-based firewall
doing NAT and suchlike.
It's probably OK for your purpose, but the EPIA motherboard I had was
somewhat flaky. I'd had the vr0 interface get wedged every few days,
and trying to use both ATA channels in an UDMA mode tended to result
in a total system hang; using only one ATA device, UDMA-100 was fine.
I never ended up putting the box into a production use as a
consequence. I've had better luck with something like the Soerkris