The rate of extermination depends on what time in the camps life your looking at. For example, when the camp was simply Auschwitz 1 at the beginning of the Final Solution program in late 1941/ early 1942 it could process 700 individuals a day from their assessment on the train platform to Crematorium I, as opposed to the horrific scale of the final months of the camps existence, in which from May - July 1944 nearly 400,000 Hungarian Jews were killed at a rate of nearly 12,000 a day (a rate which the crematoriums could not handle and the bodies were burnt in open pits)^1

The camp was designed to operate on a round the clock basis, supposedly with the means of disposal from the amount of corpses they had to process, but like already mentioned the furnaces were coke fired and relied on the victims fat to speed up the burning process (as a result the furnaces often broke down from the amount of use they were getting as well as the walls of the chimney being clogged with human fat)^2. Combined with a large workforce of press ganged Jews, Auschwitz could preform multiple gassings in a day, as opposed to the cruder camps that came before it in the early days of the Final Solution.

(1,2 *Adrain Weale Army of Evil: A History of the SS)