Difference between running a 32-bit program on a 64bit machine performance wise.

[redwraith]

What is the difference when running a piece of code compiled for the 32 bit architecture on a 64 bit machine. Does the 64 bit machine emulate these instructions (if so, what is the approximate penalty) or does it have some kind of 32-bit native mode. What is the difference in performance of this and why?

Best regards

[AndreyKarpov]

See: Support of 32-bit applications in the 64-bit Windows environment.

[Master-Eng_-Pro]

Quoting Andrey Karpov

See: Support of 32-bit applications in the 64-bit Windows environment.

There is no differnce as far as running the 32 bit application on 64 bit windows because there isfull support for earlier windows application in64 bit windows as in the previous windows such as Xpwas fully supporting the 16 bit application easily that is the quality of new windows

[okiprasetiyok]

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[Anthony_B_Intel]

It depends on whether the 64-bit machine is based on the IA-64 architecture or the later Intel 64 architecture (previously called EM64T).


IA-64is pure 64-bit, requiring an emulation layer to run 32-bit code, which can be costly depending on your application behavior. This model is primarily used in the Itanium product family.

The Intel 64 architecture supports IA-32e mode which supports 32-bit applications natively. There may still be some fixups required when running 32-bit applications on 64-bit operating systems, but the overhead should be modest.