Re: What firewall are you using that is capable of 50 Mbps?
I built a small computer with an Atom D510 processor with 2 GB RAM, 2 gigabit NICs (one integrated and the other is a PCI card I believe), and I use a compact flash card for storage (OS + logs). I've had it for like 2 years so far and it still works very well. It's running pfSense 2.1 BETA.