AMD Phenom II X4 970 needs just a bit more to equalize the Phenom II X4 and Core i5-700 series in rights. Both product lines offer solutions that currently give you most performance for your money. Of the rest, Phenom II X6 1055T may be the least obvious choice. Subjectively, an unlocked Phenom II X6 1075T seems a better variant. Of course, if your tasks are well-parallelized.
Source: iXBT Labs