If 32 bit softwares works with a 64 bit Operating system

[Guest]

I want to know if 32 bit softwares works with a 64 bit Operating system.
And if so, if these software are able to use more that the regular 3 gigs RAM
if they need it. So to be clear, If I buy a 16 gig 64 bit computer, and my 32
bit cad software need 8 gig to do a specific job, will windows be able to
give the application the ram it needs to process is things ?

 

[dobey]

I want to know if 32 bit softwares works with a 64 bit Operating system.
And if so, if these software are able to use more that the regular 3 gigs
RAM
if they need it. So to be clear, If I buy a 16 gig 64 bit computer, and my
32
bit cad software need 8 gig to do a specific job, will windows be able to
give the application the ram it needs to process is things ?

Intel and AMD desktop 64 bit CPU support 32 bit instructions, (meaning 32
bit software will run).

What machine are you currently using 8 gig or RAM on for these CAD projects?

If you are using a Windows machine, are you sure your not confusing RAM and
a swapfile or something? I know some ot the server software supports a large
amount of RAM.

The amount of RAM a machine can handle depends on the chipset as well as the
OS.

I would assume if your motherboard would accepts 8 GB of RAM, and the OS
recognises it then it would seem so.

This might be a question for the CAD software programmers.

 

[Ken Blake, MVP]

I want to know if 32 bit softwares works with a 64 bit Operating system.

Generally yes, although there are some exceptions.

And if so, if these software are able to use more that the regular 3 gigs RAM

There is no "regular 3 gigs RAM." 32-bit versions of Windows have a
4GB address space, but some of that space is used by hardware and not
available to the operating system and applications. The amount you can
use varies, depending on what hardware you have installed, but is
usually *around* 3.1GB. I've seen numbers as high as 3.5GB.

if they need it. So to be clear, If I buy a 16 gig 64 bit computer, and my 32
bit cad software need 8 gig to do a specific job, will windows be able to
give the application the ram it needs to process is things ?

If you have a 64-bit computer with 8GB of RAM and 64-bit Windows,
Windows can make 8GB of RAM available to itself and its applications.
Windows itself and any other running apps will use some of that 8GB,
so the CAD program can't get the full 8GB.

However, whether a 32-bit program can make use of that much RAM is
doubtful. I don't know for sure, but my guess is that most, if not
all, 32-programs are aware of the 4GB limitation and may not be able
to access more than that.

 

[Jim]

I want to know if 32 bit softwares works with a 64 bit Operating system.
And if so, if these software are able to use more that the regular 3 gigs
RAM
if they need it. So to be clear, If I buy a 16 gig 64 bit computer, and my
32
bit cad software need 8 gig to do a specific job, will windows be able to
give the application the ram it needs to process is things ?

No.
It may be possible for a 32 bit application to use more than 4 GB of virtual
address space if it is written to use the PAE instructions.
There aren't many such programs though.
It is my understanding that there is no operating system support for these
instructions in XP or in Vista. Whithout OS support, even
such a program would be dead in the water.
Jim

 

[Tim Slattery]

If you have a 64-bit computer with 8GB of RAM and 64-bit Windows,
Windows can make 8GB of RAM available to itself and its applications.
Windows itself and any other running apps will use some of that 8GB,
so the CAD program can't get the full 8GB.

However, whether a 32-bit program can make use of that much RAM is
doubtful. I don't know for sure, but my guess is that most, if not
all, 32-programs are aware of the 4GB limitation and may not be able
to access more than that.

I don't think so. AFAIK, a 32-bit program would run in a 32-bit
virtual memory space, just as if it was in a 32-bit OS. After all, all
the addresses it uses have to be 32-bits long, right? So there would
be no way for it to address anything higher than 4,294,967,296. 16-bit
apps running under a 32-bit OS worked the same way: the apps didn't
know about 32-bit addressing, they were restricted to their 16-bit
address space.

 

[Bob I]

Usually yes, BUT you would be a bit more sure if you asked the tech
support people that make this cad software. THEY would be the ones that
would know.

 

[Ken Blake, MVP]

I don't think so. AFAIK, a 32-bit program would run in a 32-bit
virtual memory space, just as if it was in a 32-bit OS. After all, all
the addresses it uses have to be 32-bits long, right? So there would
be no way for it to address anything higher than 4,294,967,296. 16-bit
apps running under a 32-bit OS worked the same way: the apps didn't
know about 32-bit addressing, they were restricted to their 16-bit
address space.

Thanks, Tim. That's much as I expected.