Memory & Virtual Memory

[Jeff]

I'm running some analysis software that is a real memory
hog. I have a dual processor with 2GB physical RAM, and a
permanent pagefile of 4GB, and still get "out of memory"
errors, though I appear to be just on the edge.

I understand a Pentium processor can address 4GB of
memory. Still, if I add 2GB of physical memory, do I have
a total of 8GB available? Task Manager currently shows a
limit of 6GB, which I thought would have been 2GB more
than is addressable.

Or is the real limit 4GB, and adding the extra RAM would
only get me to my out of memory error faster?!?

Thanks.

 

[Guest]

I'm just curious, what program/data would consume that
kind of memory ? Is it a fairly recent program or is it older
and written for more constrained system resources ?

When you run the program, what does TaskMgr/Processes
show for peak memory usage VM size ?

 

[Alex Nichol]

I'm running some analysis software that is a real memory
hog. I have a dual processor with 2GB physical RAM, and a
permanent pagefile of 4GB, and still get "out of memory"
errors, though I appear to be just on the edge.

I understand a Pentium processor can address 4GB of
memory. Still, if I add 2GB of physical memory, do I have
a total of 8GB available?

No. The instructions in the program are 32 bit ones, which means that
they cannot handle any address bigger than that - ie 4GB. That is an
absolute limit of the CPU design, only to be overcome with the new 64
bit processors, Or by programs which handle some type of segmentation
themselves to map a number of GB segments from some file storage *it
* handles. Rather as Expanded memory allowed DOS to use more than a
single 1MB of RAM in a segmented 16 bit addressing. The windows server
systems can handle larger RAM in that way - but still only to provide a
4GB VM space to any individual application (and with part of that
taken for System purposes)

 

[Jeff]

I got directed to a section in the prograsm documentation
that referred to a /3GB switch in boot.ini. From what you
are saying, I'd assume that might help with the total
number of user programs running, but not this one.
Thoughts?

Thanks for your input.

 

[Jeff]

No, it's a new program, ANSYS v 7.1, which is an FEA app.
With only it running, it trips out at just about 2GB.