'ok, in theory my system has a latency of 8ms. i have confirmed this value on my brandnew pentium4-3GHz with a simple patch that just connects the outlet of the [ adc~ ] to the inlet of the [ dac~ ]. Now i wanted to fiddle around with my over-hyper-super-cool-guitar-wha-effect-fuzzer patch and it doesn't produce any intelligent output but clicks and crackles. i have to resize pd's audiobuffer to a 200ms to make them go away. now the effect is not usable for me any more.'

because of cpu-bursts, pci-bursts, dma-bursts and i don't know what else, the system-latency will often be unachievable. so what ?

• hardware :

  get the newest !

  seriously, we need a list of which hardware-specs are important

  • graphics(!)
  • ethernet(?)
  • DMA-controller
  • harddisk (esp. when doing soundfile recording/playback)
  • ...
• operating system :

  of course this depends on your OS....

  • linux:

    lowlatency-patch, preemptive-patch, 1kHz-patch

    ...

  • windows:
  • macOS-X
• driver :

  most probably nothing you can do here

• pure-data :

  ???

• patch : here could be done most
  • algorithm: use other, less cpu-expensive algorithms
  • soundfiles:
    • use a fast separate harddisk (RAID) for your sound-files
    • use tables instead of reading soundfile on-the-fly from disk (note: be sure, you have enough RAM)
    • inspection of the [ readsf~ ] code. does it block the main-process ?
  • messages vs. signals:
    • generally, calculations done in message domain are less expensive than calculations in signal-domain, because they are only done every now and then.
    • message-calculations at or near sample-rate are (supposed to be) highly inefficient. rather use signals for this
    • complex calculations in message-domain might cause peaks in the CPU-load, resulting in dac-slips (if the audio-buffer is to small). pd does not attempt to schedule messages (being asycnhronous by definition). write your own scheduler with the aid of [ delay ], [ pipe ] et al.

    note that [ del 0 ] doesn't mean "zero delay" but "as soon as possible"