Thanks. Looks about the same -- we're both running at about 75% bandwidth efficiency. So, it looks like the higher frequency doesn't help, but also the extra wait state doesn't hurt.
I wonder if there's any way to get better than 75% efficiency. The max memory bandwidth for this system should be 5336 MB/s.
Edit: I killed some apps just to see if I could get a little closer to your bandwidth. My 533 is within 0.5% of your 667.