This figure is a plot of time in seconds vs the number of points per zone for the following six CGNS version and data format combinations.
The results for all but the two XML data format cases are essentially the same. For 100, 1000, and 1000 points per zone, the time is around 0.05 to 0.08 seconds, increases to about 0.2 seconds for 105 points per zone, 2 seconds for 106 points per zone, and 20 seconds for 107 points per zone. For both XML data format cases, the time is about 0.02 seconds for both 100 and 1000 points per zone, then increases linearly to a little over 100 seconds for 107 points per zone.