I'd like to build an inexpensive MythTV system with an old Pentium 4, 1.8 GHz as the backend. It will record OTA HDTV (perhaps from the HD Homerun), remove commercials, rip DVDs, etc. I'll administer it and schedule recordings through the frontend running on an old laptop. To watch recorded content and DVD ISOs, I'm considering using the Asus O!Play HDP-R1 via UPnP.
I'd appreciate your thoughts and comments on running such a setup.
However, I don't do any commercial flagging, transcoding, or DVD ripping with this system. It only records video from my HDHomerun and serves it to my Ion based frontend. Your P4 should be more powerful than this, so no I'd say there should not be any problems using it for a backend. Might be a little power hungry though...
I'll soon be moving it to a bigger case, because it's going to be running a 6TB RAID5 array (4x 2TB Western Digital Caviar Green).
That box you linked to looks nice. It does take SO-DIMM memory (Laptop memory) so be mindful of that when shopping for memory. Ion 2 will also accelerate Xvid/Divx videos as well. My Ion 1 handles Xvid pretty well, but it does struggle with a couple of really high bitrate videos.