iPhone Compile Architecture: Standard vs Optimized

This is something stupid I probably should know, but Googling fails me:

When compiling the binary I'm going to submit to the App Store, in the Project Info -> Build tab, there's an "Architectures" option. The default is "Standard" but I noticed there is also "Optimized"

Which should I use when submitting to the app store? I have been u开发者_如何转开发sing Standard all along w/ my ad hoc testing...

Thanks.

Optimized will run somewhat faster on the 3Gs. If you like you can check that and test a bit on the 3Gs, just to make sure all is well.