When you compile your application in 4D v11 SQL on a Intel-based machine, does it then not work on a PPC-based machine?

The answer is it's up to you! If you need support for both processors, make sure that 'Compile for PPC and Intel Processors' is checked in 4D Preferences.

Preferences -> Design Mode -> Compiler -> Compile for PPC and Intel Processors (Mac Intel and Windows)