My personal opinion is your scores are fine. I think the difference is the CPU, the mobo and the RAM.
I have the the AN832 SLI Deluxe and it was developed to run in conjunction with the 3500LLPRO RAM from Corsair. I gather that there will be better memory control and transfer of info across the bus since ASUS designed the board for that RAM to run natively @ 2-3-2-6.
I did not have to alter my timing at all.
So if everything was apples to apples, CPU-RAM-mobo and your scores were lower than mine, it may be suspect.
BTW what brand is the 7900?