There seems to be two kinds of depictions of a Central Powers victory in Alternate History. The first is a swift German victory by the end of 1914 or practically assured by the end of 1914. PODs for this usually involve Germany winning the Race to the Sea, winning the Battle of the Marne, etc. The second is a German victory in 1918, either because the Americans haven't joined the war and the Entente is exhausted or the Spring Offensive is more successful. Which is more plausible?