There was a hotfix released for a performance issue with the Arrival Overview form. However some people may still experience performance issues when going to Inventory Management > Periodic > Arrival Overview and changing the setup name to return order. This has been seen when you have a lot of backorders. To resolve this you can add the following line to the buildOverviewQueryReturnOrder method of the WmsArrivalOverviewGeneration class.
Depending on your data you may need to add additional filters or indexes to assist in optimal performance on this form.