It can do the China to California run in 4 days.

The Emma Mærsk
Largest fossil burner on the seas. Largest ship in existence (along with the 7 others of the same class being built)
http://en.wikipedia.org/wiki/Emma_M%C3%A6rsk
Largest diesel engine ever built, burns bunker oil. Can carry 11,000 container units. Designed primarily to do the Walmart Run and China-Japan and China-Rotterdam & Bremmerhaven. On the last, cannot fit in Panama Canal, but will be able to do the new northern route (Artic Ocean).