Problem getting through the wizard, won’t reach the finish button in realistic time frame

A wizard contains of  6 steps before finish button.

step 1 - 150 rows

step 2 - 80 rows

step 3 - 9000 rows

step 4 - 160000 rows

step 5 - 20 rows

step 6 - 30 rows

then finish.

 

To get trough this is a pain. It goes quick until step 3. To list 9000 rows is about a minute wait. But, step 4 is over 1,5 hour of just listing the rows in the wizard. How come it is taking such a long time? There is no difference between Fusion and classic client, both are stopping on step 4 in the wizard.

Feedback, pls

Christian