mmmm... is your phenomII overclocked?
If you've got it clocked up to 3.8-4.0ghz then you've got enough cpu power for the most part. I would just look at using your extra cash for a better gpu and an ssd. You'll find a much better bump in performance upgrading in that direction.
Don't get me wrong, that intel is a fairly significant improvement, however that phenomII is the definition of "good enough"... almost nothing needs more cpu power then that PhII can give you.
That made up my mind, i'll keep this am3+ cpu for now, thank you for the help