Greetings,
Only one rev of your board (v1.1). What BIOS version are you running?
Start here
Channel 0: DDR3_1, DDR3_2
Channel 1: DDR3_3, DDR3_4
When enabling Dual Channel mode with two or four memory modules, it is recommended that memory of the same capacity, brand, speed, and chips be used for optimum performance. Mixing is not recommended
Have you tried the new ram is slots 1 and 2 (only) no other RAM installed. what are the results?
You may have to set the memory specs manually. Try a different BIOS (newer)