I'm not sure but I find I get better timing if I use my DAW (Logic) as the master and my MPC-2000XL as the slave, if I set it the other way I get a lot of drift from Logic and it will not sync propperly/tempo drifts like a **** but then I am using a cheap interface (M-Audio Fast Track Pro) and to be honest I think M-Audio suck when it comes to this sh*t, when I had an Emagic midi interface few years ago that thing was rock solid