My 286 with a Voyetra Sequencer, which is still in use, is much more reliable then my modern PC in terms of tracking and timing.
You need a real time system, perfect task separation and _not_ an unreliable USB interface.
It has absolutely nothing to do with CPU power.
Also my Atari with Cubase 3.1 is much much better with MIDI timing then every modern PC setup.
Think about it. :-)
Just to be clear I'm talking about digital audio, not MIDI. I ran Cakewalk on my 386/486 as well, it worked great including SMPTE sync over to an analog tape machine