Aeolus is a synthesized (i.e. not sampled) pipe organ emulator that
should be good enough to make an organist enjoy playing it. It is a
software synthesizer optimised for this job, with possibly hundreds
of controls for each stop, that enable the user to "voice"
his instrument.

Main features of the default instrument: three manuals and one pedal,
five different temperaments, variable tuning, MIDI control of course,
stereo, surround or Ambisonics output, flexible audio controls
including a large church reverb.

Aeolus is not very CPU-hungry, and should run without problems on a
e.g. a 1GHz, 256MB machine.