Gallons per minuter is not a measurement made on these or any washers.
If you will to compare energy ratings between washers then the following link will be helpful to you:
Energy Star Appliances
Water usage is the current way of measuring a washer efficiency. This model is an Energy Star and you can check the statistics the the about site.
On an HE3 there is not low, medium or high water level to be set. The water fill is calculated by how many and what kind of clothes are in the machine.
I hope this information is helpful to you but submit another question with any additional details for further assistance.