I have to withdraw my comment. It is NOT a good idea to put a SATAIII SSD in the optical bay. It gives random freezes. Swapping it with a HD is indeed better. Better read/writes too. Only downside is that SMS won't work on the optical bay so treat your baby with care. Also Sleep issues might occur when placing a HD in the optical bay (a total freezing system). I already wasted a HD that was in the optical bay.
No problems here with a Samsung EVO in the optical bay. Only downside that is not really fast (80-90 mb/s) but amazing performances on booting time, shut off and opening programs.