"While the i7-970 may only be slightly slower than the i7-980X EE out of the box, it’s a whole new game when it comes to overclocking. This is because while the i7-980X EE is an absolute beast, hitting 4.4GHz on air, we were only able to overclock the i7-970 from 3.2GHz to 4GHz.
While this isn’t a bad overclock, and did boost performance considerably, it’s a much worse overclock than the i7-980X EE. In fact, this result makes the i7-970 one of the worst Core i-series CPUs for overclocking that we've seen."
bi-tech
anandtech