RED LD FWD DROP

I have 2 open-can red LDs, one from a 20x lite-on and one from a 20x LG H55N. Both have the same external appearance, but the LG one seems to have a much lower forward drop at a given current. For instance, it has 2.38V across at 180mA, whereas the lite-on one reaches 2.51 volts at only 150mA.
So, what voltages do you measure and at what current? I dont know if my expectation is plausible or not without any datasheets, but Im guessing that those LDs with relatively lower forward drop are capable of handling safely more current and providing higher optical yield.