What computer do I need to run DirectCsound in realtime?
It depends of how much synthesis power do you need. I recommend at least a Pentium 133 MHz which can handle up to 50 oscillators in real-time (at 44100 Hz). However actual polyphony depends by several factors such as sampling rate, computer motherboard, RAM type, cache memory size and the buffer size you set in the command line call (flag -b).