| Processor load *shouldn't* (carefully qualified) make any difference on any of this--phase, timing, whatever, so long as the DAW is reasonably sane.
Think of it as an assembly line, with a bunch of samples coming along a bunch of different conveyor belts. At the places where parts come together (busses, sidechains, etc.), the partially-assembled mass stops and waits for all of the parts to show up before moving on to the next station.
Under normal circumstances, the line can move faster than the average required (the output sample rate.) So a bunch of completed assemblies pile up in a queue (the output buffer) and the whole thing comes to a halt until the queue opens up a bit (samples are clocked out.)
Under enough load, the assembly line falls behind; if the output queue empties, you get pops and clicks or the software quits.
But the important thing to note is that instantaneous timing should *not* be an issue, as the only place where time is even considered is at the D/A. No jitter is possible in the purely digital world.
It's slightly more complicated when there is A/D in the picture; it just means that the assembly line comes to a halt either when the output buffer fills or the input buffer empties. As long as the output buffer is never empty, nor the input buffer is never full, things will work. The combination of the two buffers defines the elasticity of the system. (This is also why your A/D and D/A need to run off of the same clock; otherwise you are guaranteed to eventually overrun or underrun if one is slightly faster than the other.)
The phrase "processor lag" simply makes no sense. If the processor has enough capacity (in combination with the elasticity of the buffering) to keep up, then by definition all the work will get done and things will work. If it falls behind far enough, the output buffer runs dry and the whole thing grinds to a halt. There really isn't any middle ground.
For the same reason, faster-than-real-time bounces (that don't utilize outboard processing) should be absolutely identical to real-time bounces.
This is not to say that software doesn't have bugs, of course. |