Langdon Alger
Banned
You're probably fine... had the same issue cramming my 970 in there (and that's the main reason I'm not even going to entertain the notion of putting a 980 in there until a smaller rebranding comes along)
Keep an eye on the temp though. Airflow could be an issue
While playing games the GPU temp hits 81 C and makes a terrible whining noise. So it's probably not great. But I have no idea what temp. my old 660 hit, so I don't know how it compares.