Memory, latency, HEXUS.PiFast
Bandwidth goes up as the memory frequency is increased from DDR3-1,333 to DDR3-1,600.And latency drops as the same timings are kept. Note that the Clarkdale chips' access latency is significantly higher than all the other CPUs'.
The single-threaded PiFast test loves clock-speed over all else. That's why the 4GHz Scan SMART system wins out here, beating the 3.6GHz Core i7 870 and 3.4GHz Phenom II X4 965 BE.