run/debug architecture choices

Am playing around with AppCode (Beta) OC - 109.37.  I'm also a huge IntelliJ fan.

If I set the SDK to one of the simulators (for example, Simulator - IOS 4.3), I get four choices of 'architecture': standard, optimized, native, i386.  Could I get an explanation of the first three? The terms 'standard', 'optimized', and 'native' could be interpreted a lot of different ways.

I'm hoping that one of those options will force the IOS simulator to do a better job of emulating the real hardware.  There seems to be much discussion about the fact that the simulator does a poor job of emulating IOS based hardware, particularly in the areas of memory usage and graphics performance.

Thanks.