Having multiple cores is fine and dandy but thats not always going to help. If you've got an audio track loaded with a shit ton of plugins, guess what, that audio track has its own thread on its own core and it all needs to be processed there. You cant split it among multiple cores, that's just not how it works.
Each track can run on its own core, but the processing on that track can easily overload its single core and after that its done. When you run out of a core, it doesn't just roll over to the next one and split the load. That's why you see so many people asking about things like "higher clock speed vs more cores" when shopping for new motherboards and cpus.. The DAW can easily splits its ENTIRE workload over multiple cores sure, but each track's own processing thread is limited to the core its started on and doesn't move from there. While you might be processing a couple tracks inserts on one core, the DAW can move other processes to another core to free up the initial ones for the tracks, but it doesn't offload those tracks onto other cores when they max out.
That said, I still doubt the MPC Software was written anywhere near as efficiently as something like Logic Pro or Cubase which can handle this stuff pretty well the more you pile on to it.
