I think what it really boils down to is the IMC in Nehalem is over engineered and slower because of it. The designed the IMC to handle not just four cores, but eight, and maybe even more (as much as 72). I doubt we will see any significant changes to the IMC as far off as Sandybridge chips. But yeah... maybe there is a bug in it. When AMD shifted to IMC, they got a huge memory performance boost. Intel appears to be taking a hit instead. CIS is a more complex scheme but you'd think that would show throw in more than just gaming benchmarks. I just wonder how what Nehalem runs with FB-DIMMs.