An i5-3570K OCed to 4.2 GHz and you're still getting lag? Sounds like something's up with your configuration. You can use the speed settings posted here as a base. Tell us if these settings run the game fine. If so, then you can gradually start increasing settings to improve the graphics. Also, note that Super Mario Sunshine is a 30 FPS game, so it's playing at fullspeed if that's what you're getting.
Another thing to point out is that maxing out the IR and AA can quickly turn your GPU into your system's bottleneck, even with a GTX 690. SSAA with the DX9 backend, for example, is very demanding when set to 9x and increasing the IR.
Another thing to point out is that maxing out the IR and AA can quickly turn your GPU into your system's bottleneck, even with a GTX 690. SSAA with the DX9 backend, for example, is very demanding when set to 9x and increasing the IR.