The Sandy Bridge architecture, aside from the die shrink and subsequent increase in clock rate which that entails, in my opinion, is not that much of an improvement over the previous i7 Lynnfield architecture (i7 860, 870, 875k, 880). Here is an article that benchmarks a Sandy Bridge CPU vs an i875k where the frequency of both processors set to 3.4 GHZ... not that big of an improvement.
Funny thing is many of the articles today are praising the chip as a big improvement over Lynnfield not making it clear that this is most likely due to the clock rate increase.
All seems condemned in the long run to approximate a state akin to Gaussian noise. -- James Martin