Win64 or Win32 for 32 Bit program

[marcouellette]

Hi All,

We will be upgrading out computer in the near future to faster PC for our Simulation Model which is a 32 Bit program.

My Question is will we see a speed improvement on windows 64 bit at all? Or will it slow it down because of the WoW layer? I am just trying to figure out if we are better staying with xp or 2000 for now.

Thanks,
Marc

 

[phisrow]

Unless you need shocking amounts of RAM, you have little to gain, at the moment, by messing around with Win64 for a 32bit app. You probably won't lose much speed; but you may have Wacky Fun with drivers, and you won't gain anything of note, except better RAM handling(not that it's likely to matter much, as your app is 32 bit).

 

[marcouellette]

The model needs about 1.8GB or ram when running. We have hit the 2GB barrier before. But since it is still 32 Bit we will never be able to access more then 2 and our current compiler doesn't support 64 bit now so we are stuck.

I was currious if we would get a speed improvement.

Thanks.

Marc

 

[bsobel]

But since it is still 32 Bit we will never be able to access more then 2 and our current compiler doesn't support 64 bit now so we are stuck.

Actually, you can access upto 3 gigs today on 32bit Windows, and even more interestingly upto 4 gigs on x64 from your 32 it app!

"Applications running in the WOW64 system on Windows XP Professional x64 Edition each have a full 4 GB of virtual memory space. Applications compiled to take advantage of the /3 GB switch will actually get 4 GB, without constraining the operating system at all, since it is running in the 8 terabytes of virtual address space that Windows XP Professional x64 Edition has for the system processes. This can have a substantial impact on memory-constrained applications, such as computer-aided design (CAD) and computer-aided manufacturing (CAM), even before a 64-bit version of the program is available."

So your 32bit program, if compiled (or marked with the imageedit tool) will have the full 4 gigs of address space available to it instead of the current 2 gigs.

Bill

 

[marcouellette]

We are using C++ Builder so I don't think we can compile for the 3GB switch. So I can still get it to work with the imageedit tool?

Will the performance decrease thought by running on WoW?

Thanks,
Marc

 

[bsobel]

Originally posted by: marcouellette
We are using C++ Builder so I don't think we can compile for the 3GB switch. So I can still get it to work with the imageedit tool?

Will the performance decrease thought by running on WoW?

Thanks,
Marc

Yep the image edit tool can set the 3gig aware swtich, which will probably just work unless your app does something 'weird' and makes assumptions about pointers.

As for WOW64, the performance is pretty close to native (I'm sure in benchmark scenarios we can prove its slower, but it's nothing like the 16bit emulation stuff since the procs are built to do this natively...)

Bill