No, CS:GO is single thread bound, it would be best to go with an i5 if you are keeping your current GPU (it's a quick upgrade if you want to do it down the road)
AMD has already admitted defeat on CMT, it was garbage when it came out, it is garbage now, especially with the IPC improvements since SB... Then again more cores was the only way they could keep up in overall performance with the horribly inadequate schedulers that they use... I would have recommended it in some cases 18 months ago, but it is dead as a dodo now.
Either way, enough with going off on tangents. Go with an i3/i5 if you want to get lots of frames on an aging engine like HL2 or ioQuake/id tech 3. Neither needs a lot of graphics power, just raw single core performance.