Which benchmarks are used to calculate IPC? I have a few problems with the numbers posted here.
I am pretty sure that Haswell's IPC improved on Ivy Bridge by less than 10%, let alone the 22.5% improvement shown here. On top of that, as far as I know, Nehalem was a significant step forward compared to Penryn, which isn't reflected here at all. All in all that should mean that Nehalem through Ivy Bridge should all have higher numbers.
Also, how does K8 regress by nearly 10% going from gen 2 to gen 3?