The mysteries of Laser Cutting unraveled here... 

Expected Speeds using a Trotec Laser large format laser system
There are two types of cuts:
1.  Seperation Cut - fast cutting
2.  Quality Cut - Cut with shiny edge 

400 Watts

Thickness Fast Cut Quality Cut
.125" 336"/min 88"/min
.25" 170"/min 50"/min
.5" 72"/min 21"/min
.75" 34"/min 14"/min
1.0" 29"/min 7"/min

200 Watts

 Thickness  Fast Cut Quality Cut
 .125" 177"/min 59"/min
 .25" 82"/min 33"/min
 .5" 35"/min 14"/min
.75" 16"/min 9"/min
1.0" 14"/min 4"/min