Omni extreme has the option to change the ram timmings so i assume if you know youre cards ram timmingsj ust change them to that when youre editing an Ultra bios. To keep the power consumtion down, just edit the voltages on the Ultra fro mthe stock 1.4v 3d ect to 1.3v like on the GT.
But be warned setting the 2d voltage to 1.1v which is on the GT and Ultra, doesnt mean youre card will run @ 400/1100 @ 1.1v, so avoiding the power confumtion all together may be imposible. Unless you have a card like mine which can run 400/1100 @ 1.1v