3570K........it is an absolute beast. While SB can hit higher OC numbers ON AVERAGE, IB can reach damn near the same numbers and runs 10-15% more efficient. Basically 4.6GHz IB is equivalent to a SB clocked at 4.8GHz..........that is a basic generalization I've read on many hardware reviewer sites. The 3570K will be able to handle anything you throw at it without breaking a sweat, no question about that. Plus, you have the Z77 motherboard so you get the new technology upgrades that come with that. I know Z77 and Ivy Bridge CPU's utilize RAM more efficiently as well as USB 3.0 and PCI Express 3.0 which was mentioned earlier. Anybody that said that the 3570K doesn't have as much "grunt" as the 2500K is outside their mind. Go with the 3570K with the HD 4000 graphics, figure out how to use the 4000 graphics along with your discrete graphics card, and rock on. Should be a no-brainer since you already have the Z77 motherboard.