they are very similar
the i7 has a bit more memory onboard to help it sort through data , its running a little faster , and it can hyperthread which means when a core is running at 60% load the processor will try and use the other 40% for something else if it needs too .
For gaming use the 3570, for encoding the 3770 is better
but both are now obsolete and replaced by the 4770 and 4670 . If they have a K on the end they can be overclocked . With no K its much harder to do that and results are limited