There's no X6 in the benchmark, but the 2 x Opteron machine could be considered an excellent point of reference. 8 very similar cores, reasonably similar clocks to the X6. In a well threaded benchmark, it's actually about 20% beastlier than an X6. Notice that FX CPU is significantly faster.
Now look here:
Bottom graph. The aging Core i7 920 soundly defeated it's newer cousin, the Core i5 2500K, despite a 700mhz clock deficit. Yes folks, that would be a regression, the kind that AMD has with Bulldozer, but supposedly Intel never has.
I trust you'll do the right thing and go trolling over the entire internet about what a failure Sandy Bridge is.