I'm not sure about dramas, but here are some movies about the Cultural Revolution:
Hibiscus Town (1987)
Farewell My Concubine (1993)
The Blue Kite (1993)
In the Heat of the Sun (1994)
To Live (1994)
Balzac and the Little Chinese Seamstress (2002)
My favorite is In the Heat of the Sun, but it's not a very typical cultural revolution movie.
The Blue Kite is probably the most realistic movie on this list.