We've been building an information appliance, trying to figure out what is the real ceiling of applications or perhaps the real floor for processor speed. Our application platform provides file serving, communications management (DSL, ISDN, Satellite, etc) in addition to home management, entertainment, etc.
Surprisingly , the other week, we were streaming (serving) 2 radio streams, 1 remote video channel, 1 remote movie, and 4 full movie windows, besides managing our home communications, all on a 1.3Ghz Duron. The video channel seemed to be the most cpu intensive, with the 4 full movie screens(VHS quality) showing no degradation of frame rates.
We're using Slackware Linux, 256MB ram, and our own custom software content control management and serving system. I recognize that this is not a normal "server" kind of environment, it just kind of puts the serving framework into perspective of 5 full MPEG decodes(without hardware accelerators), plus the network streaming issues. I never would have guessed a 1.3Ghz Duron could do it. .