Originally Posted by terenz
The 340-300 (assuming LA doesn't have -500s or -600s, or even -200s) is known for lacklustre takeoff performance (i.e., it is underpowered). The full load and relatively long range may account for the slow and hence less noticeable rate of climb.
It's said that the 340-300 doesn't climb, anyway, in the traditional sense - it only gains altitude because of the earth's curvature.