A graphics processing system comprises at least one memory device storing a plurality of pixel command threads and a plurality of vertex command threads. An arbiter coupled to the at least one memory device is provided that selects a pixel command thread from the plurality of pixel command threads and a vertex command thread from the plurality of vertex command threads. The arbiter further selects a command thread from the previously selected pixel command thread and the vertex command thread, which command thread is provided to a command processing engine capable of processing pixel command threads and vertex command threads.