Some of the HP T-series thin clients are x86 and can accept a PCI-E riser. I ran one with a sempron 2100+ (fanless) and an Intel Pro/1000MT 2-port PCI-E card.

Some of the HP T-series thin clients are x86 and can accept a PCI-E riser. I ran one with a sempron 2100+ (fanless) and an Intel Pro/1000MT 2-port PCI-E card. It had 1GB of RAM and 1GB of solid-state disk-on-module, but the module used a weird reverse-gender 2.5" IDE connector, so I had to use pin headers to adapt it to an external USB HDD reader to install pfSense on it. After that though, it ran great for a few years until the motherboard died. In all, $100 well-spent for a quiet and small pfSense box with enough power to handle 100mbit internet at wire speed. Here's an example of what you can get these days: http://www.ebay.com/itm/NG816AA-HP-Compaq-GT7725-Thin-Client-AMD-Turion-X2-2-3GHz-2GB-1GB-Quad-Monitor-/290979793321?pt=US_Thin_Clients&hash=item43bfbf49a9 http://www.ebay.com/itm/NG816AA-HP-Compaq-GT7725-Thin-Client... ($60 and it has either a PCI or PCI-E slot). Now I'm happily on a Ubiquiti EdgeRouter Lite, which is a great little Debian ARM box that runs Vyatta for $100: http://www.ubnt.com/edgemax http://www.ubnt.com/edgemax (protip: learn the CLI; it's very similar to Cisco's IOS)