In games it's just a smidgen faster than a 3570, probably 5% or less difference assuming the same clock speed. So essentially you can just use that as a reference.
I don't think so, the i5-4570 is the cpu that is replacing the i5-3470 not the i5-3570/k top of the line cpu that is replaced by the i5-4670/k so I believe that you misguided the OP in his regards. The i5-4570 should perform ~5% better than the i5-3470 so you could research those benchmarks. I myself and looking to purchase this cpu here shortly. Good Luck!