Someone already asked about drive differences so maybe I can ask something else:

Is the data in both environments the same or have you rebuilt indexes, refreshed everything, restarted sql server to get a "clean" test for both. -- or does production have more data, and not as "clean" as the Lab Servers? (Though assuming production box you don't have that opportunity maybe?)

Though I think you already checked "select" from sys.configurations - if you haven't you could compare there too, but guessing that's not the place.

Shot in the dark - could your recovery model be different in Prod and TestLab?