What's the difference between installing 32bit or 64bit apps on a 64bit Windows?

windows-7 windows-vista installation 32bit-64bit
Andrei picture Andrei · Nov 2, 2010 · Viewed 30.3k times · Source

So apparently, you can install both 32bit and 64bit compiled applications on a 64bit Windows system (Vista or 7).

What's the reason why both versions are able to run on the 64bit OS? Is it good practice to install 64bit apps on 64bit OS? Any advantages/disadvantages to combining 32bit apps with a 64bit OS?

Thanks!

Answer

Michael Borgwardt picture Michael Borgwardt · Nov 2, 2010

What's the reason why both versions are able to run on the 64bit OS?

If the OS couldn't run any old (32bit) apps, nobody would want to use it. So they had to find a way.

Is it good practice to install 64bit apps on 64bit OS?

Generally yes, they can use more memory and may run somewhat faster. However, it's not possible for a 64bit app to call a 32bit DLL, so you can run into problems.

Any advantages/disadvantages to combining 32bit apps with a 64bit OS?

Not really, except of course that they won't be able to use more than 4GB RAM, and may run a bit slower than they would on a 32bit OS on the same hardware.

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