upgrade strategy

Hi,

I have upgraded the power supply to a 36VDC secondary, and reading at
the rectified, filtered output showed 59VDC. However the G201 still
can only manage 14ipm with the Sherline and 3.2V 2A steppers (half-
coil) with set-resistor 18 ohm. Seeing other reporting much higher
speed, I can only assume that the following may be the cause of the
low performance:

1. unshielded 22AWG motor cables (less than 2 feet)
2. less than satisfactory pulse train. (deskNC for windows)
3. unshielded data cables. (used stranded cables before. Now replaced
with solid core twisted pair taken from those cables used for wiring
computer network)

The problem is getting suitable shielded cables. Supplier only sell
such cables in large roll. Any suggestion how I can begin to try to
tackle the above?

Thanks

keongsan