But in my opinion, if you are already spending on 2x670, why not spend a few more $ to get the i5-3570K/2500K or even i7-3770K?
+1 Agreed 100%. Just get an i5 or i7 if you're spending that kind of money on GPU's. My best guess is that, yes, a 2120 will slightly
bottle neck SLI 670's, but by how much, I'm not sure.