The
i5-520M is based on
Westmere architecture while the
E5-2651 v2 is based on
Ivy Bridge.
Using the multithread performance as a reference, the i5-520M gets a score of
33.1 k points while the E5-2651 v2 gets
415 k points.
Summarizing, the
E5-2651 v2 is
12.5 times faster than the
i5-520M. To get a proper comparison between both models, take a look to the data shown below.