What's the benefit of 200Khz?
50Khz gives you a longer pulse width, which can be a benefit with some drives.

The fact that he's had this issue with both Geckos and Leadshines, means it's probably not the drives.

That would point to maybe the power supply, an issue with accel/velocity settings, or a mechanical issue.

You said the motors are very hot? What are the motor specs, and what do you have the drive current set at?