Hi,
First of all apologies if this is not the right forum.

This is a first of its kind for me. There is an existing 32 bit C application that needs to be ported to a 64 bit machine. Now apart from taking care of pointers, size of int, conversions, Endian-ness, so and so forth, there is something else that has to be answered.

Perhaps the question will be vague and ideas incoherent. So please bear with me.

I have been asked to also find out, what can be suggested by us to the end customers as a good reason to increase RAM (why the same increase would not do the trick in a 32 bit machine, but in 64 bit machine)?

So lets take a 32 bit machine with 512 MB RAM.

The virtual process address space is 2 ^32 - 1.

In a 64 bit machine it will increase to 2 ^64 - 1.

But will the increase in the RAM, not be beneficial in both the cases? I mean, and I could be wrong here, I think the question is perhaps not correct technically, since an increase in the RAM will help in either case.

Putting it more strictly, can there be a case when an increase in the RAM would only benefit a 64 bit application on a 64 bit machine, and not a 32 bit application on a 32 bit machine?

Any pointers as to how to proceed to investigate will be highly appreciated.

Thanks in advance,
Anoop.