The oldest computer I've gotten PMC running on was a Dell Latitude D610, which has Intel 915GM graphics.
I recently tried running PMC on a computer with Intel 845 (or 865, something in the 800's), and only got a segfault early in the process. The setup between this computer and the Latitude is basically the same (both running Lubuntu 14.04.1), and both support SSE2 (afaik anyway; I believe I saw a SSE2 mention in dmesg on the older computer).
So I'm wondering what's the oldest hardware PMC would run on, or if there's any actual hard requirements (like OpenGL 1.2, specific GL extensions, etc).
Plex Home Theater
Windows, Macintosh, Linux — Minimum requirements
Intel Core 2 Duo processor 1.6 GHz or better
At least 1GB RAM for Windows/Mac OS X
Windows Vista SP2, Windows 7 SP1, Windows 8
Mac OS X Snow Leopard 10.6.3 or later
Ubuntu, Debian, Fedora, CentOS or SuSE Linux
Windows, Macintosh, Linux — Recommended configuration:
Intel Core 2 Duo processor 2.4 GHz
At least 2GB RAM
Windows Vista SP2, Windows 7 SP1, Windows 8
Mac OS X Snow Leopard 10.6.3 or later
Ubuntu, Debian, Fedora, CentOS or SuSE Linux
Lower-Powered Computers
If you have an older PC or Macintosh computer, you might find the addition of a Graphics card that supports H.264 hardware decoding useful for smoother playback in the player App. Generally, any modern graphics card will support H.264 hardware decoding. Macintosh computers generally aren't upgradeable unless they're a MacPro.
For Windows
Any graphics card that supports DXVA 2.0
Windows Vista SP2, Windows 7 SP1, Windows 8
For Macintosh
NVidia 9400M, GT320/330M graphic chipsets or better