I just did a little test. not sure how accurate it is though but, i overclocked my core i7 940 and it seems the max bclk i can reach with this chip is 210 and the max frequency multi is x23 and 23x210 = 4830.
And from reading through overclocking forums it seems the max bclk of the core i7 920's is 230 and with a max multi of x21 = 4830.

So is there any real difference here besides the price?