The new pfSense m1n1wall router is doing great so far. Here’s what happens when I saturate my 12-megabit cable line for a while (starting just after 18:30). Clearly, it’s not really breaking a sweat. And it’s barely warm to the touch.
This does give a decent indication of how much throughput it could handle, though. This is the 500 MHz Geode model. I imagine it would start bottlenecking a bit at about 50 Mbit/s sustained. Of course, if you have that sort of bandwidth, you can probably spare a few hundred bucks and a few cubic feet more for a low-end PC to run pfSense on. Even the cheapest PC desktop CPU you can buy will be able to handle complete saturation of any internet connection that we’re likely to see in any reasonable-sized office, company, or school.