AQTime includes two packages: AQTime x86 and AQTime x64. The difference is in the type of applications they can profile and in supported operating systems.
The AQTime x86 package contains modules, files and components for profiling 32-bit Windows and .NET applications. Use this package to profile 32-bit applications on 32-bit Windows operating systems. Note that AQTime x86 can also run on 64-bit versions of Windows. However in this case, the Performance and Function Trace profilers can use only the Elapsed Time counter. The other counters are not available.
The AQTime x64 package contains specific modules and components that are used to profile both 32- and 64-bit applications. Use this package to profile 32-bit and 64-bit Windows and .NET modules on a 64-bit Windows operating system (this package can run only on a 64-bit OS). Note that the Performance and Function Trace profilers can use only the Elapsed Time counter. The other counters are available if the operating system is running in debug mode. For detailed information on peculiarities of running AQTime x64, see Profiling Under 64-bit Platforms.