A dual channel showerhead comprising a first plurality of channels formed in the back surface of the showerhead and extending from a first end to a second end, a second plurality of channels formed through the thickness of the showerhead and extending from a first end to a second end, a first end plenum in fluid connection with the second plurality of channels at the first end and a second end plenum in fluid connection with the second plurality of channels at the second end. Processing chambers including the dual channel showerhead and a blocker ring separating the edge ring from the pumping ring are also discussed.