It doesn't flinch at maximum speed. I can't measure it under cutting load at the moment because there's some dust-sensitive stuff in the room, but jogging at max speed I can't even measure 0.1V variation on the output pins of the supply. Steppers under load should only consume marginally more power i'd have thought.

I'm running with the 3Nm steppers that everyone sells, along with the 4.2A drivers.

One test I can't do is a hardware e-stop, to see what voltage gets pushed back through the drivers with a sudden stop. I'm still only wired into software e-stop circuit (not good), so I can only decelerate at the max values EMC2 allows. Still, with 7V of headroom to the 50V max which the drivers can cope with, hopefully no problems...