If you have 1600mhz ram, I advise sticking to that speed as it's not that much of a gain to 1866, and honestly that overclock on ram isn't going to play nice with nice timings on most 1600 chips.
Sounds like you're running turbo multipler changes. Not a bad idea. However that processor could probably go to 4.0Ghz and run turbo above that. I however hate the idea of turbo and refuse to use it. I am personally sitting at 4.0Ghz as my power saving setup and love it. When I go to play some games later I'll be holding 4.4Ghz and running a little hotter.