diff --git a/oommfc/drivers/driver.py b/oommfc/drivers/driver.py
index 5e510338..9920f067 100644
--- a/oommfc/drivers/driver.py
+++ b/oommfc/drivers/driver.py
@@ -229,6 +229,7 @@ def drive(self, system, /, dirname='.', append=True, fixed_subregions=None,
                 # test_sample-Oxs_TimeDriver-Magnetization-01-0000008.omf
                 omffiles = glob.iglob(f'{system.name}*.omf')
                 lastomffile = sorted(omffiles)[-1]
+                # pass Field.array instead of Field for better performance
                 system.m.value = df.Field.fromfile(lastomffile).array
 
                 # Update system's datatable.