What hardware capabilities do I need to consider when designing a CNC system to take advantage of the high output rates of an ESS in Mach4?  Thanks

As far as the PC is concerned, the official word is...

Mach4 Recommended Requirements:

PREFERRED: 32 or 64-bit Laptop or Desktop – Using an External Motion Controller
Windows XP, Windows Vista, Windows 7, and Windows 8
An appropriate external motion controller
Mach4 Plugin for the selected Motion Controller
2Ghz CPU
1GB RAM
Video Card with 256MB RAM(Large G-code files, especially 3D files will require a video card with 512MB RAM or higher)

My recommendation here would be for a video card with at least 1GB RAM.

As far as the machine mechanicals are concerned, well, I think that would depend on the CNC working area, design/type of CNC and the speed at which you need the axes to move.

Tweakie.

Since the ESS is an exrernal motion board generating pulses separately from the PC, I was assuming that limitations on utilization of the high output rates possible by the SmoothStepper would be from the drives, encoders and motors.  Since I hope to use servos, are there some that can utilize high pulse rates for speed or resolution and others that can not?  If the high output rate is not actually useable then I might just get a motion board limited to 100 KHz and save money.

Thanks

Marcus Freimanis says that the Gecko servo drive can handle 350 kHz input frequency so with a 500 line servo it can run the motor at 10,500 rpm.  That is the information I was looking for.  The speed of the motor is entirely based on the pulse rate and encoder count.  So this justifies trying some of the small servos that are available today to see how much faster they can run as compared to steppers.  It makes it worthwhile to get a high pulse rate motion board in my mind.