Whatis Mem use for multiple instances same 32bit program on Win7 64bit

Hello,

My question stems in 2 parts.

1. If I have a primarily single threaded 32 bit application that I want to run multiple instances of on a Win 7 64 bit machine...in order to take advantage of throughput on 2xquad core cpu's
a. Will each instance of the 32 bit application be limited to 2GB of 32 bit addressable memory?
b. Will the total memory available to all of the running 32 bit applications be only 3.25GB or will a machine with say 64GB of memory parse out 32 2GB partitions to 32 unique windows of an application?

2. If the application has driver interfaces only certified in Windows XP (and not functioning in Win 7 (32 or 64 bit)), what is the impact of question 1 above on running multiple instances of the same application in XP SP3 compatibility mode (e.g. are there additional memory/graphic limits imposed)?

Thanks in advance for taking a look at my questions! :)

BSL

1. If I have a primarily single threaded 32 bit application that I want to run multiple instances of on a Win 7 64 bit machine...in order to take advantage of throughput on 2xquad core cpu's

It will still be limited to 2GB and won't take advantage of Quad core processing unless it has been programmed to do so and if it has the capabilities to do it. Old software won't benefit at all

a. Will each instance of the 32 bit application be limited to 2GB of 32 bit addressable memory?

Yes

b. Will the total memory available to all of the running 32 bit applications be only 3.25GB or will a machine with say 64GB of memory parse out 32 2GB partitions to 32 unique windows of an application?

Each application will get up to 2GB

2. If the application has driver interfaces only certified in Windows XP (and not functioning in Win 7 (32 or 64 bit)), what is the impact of question 1 above on running multiple instances of the same application in XP SP3 compatibility mode (e.g. are there additional memory/graphic limits imposed)?

It should make no difference but if the XP driver is not digitally signed windows won't even allow it to be loaded unless you disable the driver signing check, the software using it might not even work. 32-bit drivers won't work on 64-bit OS, in that case you should use XP mode

yowanvista - thank you for your reply - very inclusive and provided me the answer I was looking for. Each instance of the application runs for many hours so it does pick the core least in use at start (it assumes another instance of itself or a cpu hog program is running) so in essence it does take advantage of the multiple cores (albeit a single threaded instance)

severedsolo - thank you as well for the additional info (the 2gb limit/application is not an issue) but if I run 6 application windows I needed to ensure that each would have it's own full 2gb and not all run in the same 32 bit addressable space of 3.25gb.

but if I run 6 application windows I needed to ensure that each would have it's own full 2gb and not all run in the same 32 bit addressable space of 3.25gb.

Windows will automatically allocate the required memory(up to 2GB for each) to 32-bit applications

it's own full 2gb

A 32-bit application won't usually use 2GB

addressable space of 3.25gb

This 3.25GB limit only applies to 32-bit systems

yowanvista - yep thanks again - I understand your reply and we are on the same page