Try raising the RAM Volts to 1.6, insteed of the default 1.5 .
i increaces voltage to 1.6v for memory in BIOS, but it doesn't help.
3 BEEP any way.
I try install Kingstone KVR1333D3N9K2\2G 2GBx1 and them WORK!
Well it had to be the Hynix Ram , That fixed it , The DP45SG that I have is running 8GB DDR3-1333-10600. Stable all day long , as long as I was not overclocking it , 1.5 volts was fine But when I turned up my QX9650 uo to 3.8 than I had to turn the ram up to 1.6 . than it was stable.