RAM usage/management of multiple 32-bit native apps in Vista x64

[Shuelessjo]

I know this is a dumb/n00b question but I have to ask it since I am about to order a new M/B with 8 GB of DDR3 (+ Wolfdale CPU) and the answer to this question will dictate my order decision.

Lets say I am using Photoshop CS3 and Premiere Pro CS3 at the same time in 64-bit Vista and I have 8 GB of RAM installed on my PC. Will these apps be able to use up to 3.2 GB of ram AT THE SAME TIME?

 

[Aberforth]

A 32bit application cannot use more than 2 GB but windows 32bit supports upto 4 GB & allocates a maximum of 2 GB per process - if there is extra data it will be dumped to page file. This holds true even if a 32bit app runs in Windows 64bit WOW64 mode.

64bit applications on the other hand can use more memory which naturally reduces pagefile usage and increases processing speed and 64bit capable CPU has more registers to process more data per clock cycle.

 

[Nothinman]

And it'll never even get to 2G because that's a VM and not a physical limit so other things like the binary itself, shared libraries, mmap'd files, etc also eat VM space. If you mark the binary LargeAddressAware it'll get to use the full 4G (minus previously mentioned overhead) available to a 32-bit process on a 64-bit OS but if the app isn't ready for that it'll crash.

 

[bsobel]

Originally posted by: Nothinman
And it'll never even get to 2G because that's a VM and not a physical limit so other things like the binary itself, shared libraries, mmap'd files, etc also eat VM space. If you mark the binary LargeAddressAware it'll get to use the full 4G (minus previously mentioned overhead) available to a 32-bit process on a 64-bit OS but if the app isn't ready for that it'll crash.

It *may* crash. We've found in testing most applications work fine in that mode, just few developers currently test for it. Thats improving with V64 since they get the full 4gig address space (as you mentioned).

 

[Shuelessjo]

Thanks everyone for the replies!
This is exactly the info I wanted.

 

[pallejr]

If I remember correctly, CS3 is made largeaddressaware from the vendor, so it shouldn't be a problem

 

[Nothinman]

It *may* crash. We've found in testing most applications work fine in that mode, just few developers currently test for it. Thats improving with V64 since they get the full 4gig address space (as you mentioned).

Yea, sorry. I'm usually more careful about my wording than that. =)