Covers a multitude of sins - VSTi, external instruments, slave machines etc.
Agree with Matt too - when it comes to mixdowns I tend to ramp it up a bit, but anything above 128 makes decent accurate playing difficult unless you adjusts your playing timing to allow for it. Come what may, the idea of anything as high as 6ms is my idea of hell.
Thank god for RME.
Ars longa, vita brevis, occasio praeceps, experimentum periculosum, iudicium difficile.