Based on leaks, they should perform about the same for strictly gaming in current games. Long-term though, the 2600 may gain a significant lead in the future due to having SMT. SMT would also be handy if you do any amount of non-trivial multi-tasking while gaming.
As medic wrote, only a few more days to go before the review embargoes drop and the benchmark floodgates bust open. Unless your PC exploded and you need a new PC on an emergency basis because your master thesis is due next Monday, it makes little sense to buy before seeing the reviews if you aren't already committed to buying Intel.