Are you running the November firmware?
The November firmware contains a bug that causes the speed of a S3 to decrease dramatically after running for a few hours. Switching to the October firmware should correct the issue.
I have no idea why Bitmain is not more forthcoming about this problem, but they did pull the November firmware from their website so I'm sure they know about it!!!
Thanks!
My problem is now solved
Thank you very much for your reply!
God Bless!!!!!