Maximum frequency of printerport and EMC

Hello !
Its now the first time that I´m trying to use the g320 Geckodrives.
Until now I used stepper drives 1/8 Step and Motor-resolution 1.8 degrees. As
software I used DINCNC. The max. velocity my mill reaches is 8m/min with 5mm
skrewballs. If I figured out correctly that means an output-frequency of 43
kHz. Now the servo-motors I´m going to use have DROs with 500 lines.
Perhaps somebodey can help me with this :
1.) is it right that these 500 lines will be interpolated to a resolution on
1/2000 turn of the motor ?
2.) I think the maximum Output-frequency of the printer-port depends on the
processor. But what is reachable with a AMD-K2-300 ?
3.) how does EMC limits this frequency ?
Thank You
Peter Meinhard