Hey, I have a i5 3570k @ 4.2 GHz, I was thinking about getting a 880 when it comes out. Can anyone give me a good estimation on whether or not my CPU will be up to par, or should I upgrade to i7 3770k?
Clock for clock, the 4000 series are a little tiny bit faster. It does not really matter in the grand scheme of things, especially not if you already have a 3xxx. And since yours is a "K", you can always just clock it higher.
1) Your CPU will be just fine, don't worry. A sandy bridge CPU that's overclocked should still be fine, even.
2) Upgrading to a 3770k would do absolutely NOTHING. For gaming, the i7 does absolutely nothing better than an i5 - the only difference is a tiny bit of L3 cashe and hyperthreading, which has nothing to do with gaming unless the game is very poorly coded.