Max mem in XP, Page File included?

[zv.odd.101]

I have been reading around the web and everybody is saying that Windows
XP(non 64bit) Supports up to 4GB of "memory". But this isn't very
specific. Rumor has it at the IT department I work at that XP will only
be able to make use of 2GB of physical RAM and that the page file is
counted as the other 2gb 'memory'. Even though windows cant use the
page file like RAM, it has to dump large sections in and out of
physical memory (or so i am told).

So what i want to know is how much Physical RAM can Windows XP make use
of and how does it make use of it? I have heard that some of the memory
is reserved for debugging and system operation. How much memory is left
over for standard applications to use?

 

[Guest]

Hi there ZV,

Pagefile is actually space on your hard drive to assist with processing
information that is loding into memory. Specifically, according to Microsoft
KB article 555223 by our beloved MVP Bruce Sanderson
(http://support.microsoft.com/default.aspx?scid=kb;en-us;555223) "When the
memory in use by all the existing processes exceeds the amount of RAM
available, the operating system will move pages (4 KB pieces) of one or more
virtual address spaces to the computer’s hard disk, thus freeing that RAM
frame for other uses."

Pagefile space is determined by default, by the amount of RAM you have in
the machine, up to 4GB. So, if you have 1GB of RAM, you will have 1.5GB of
hard disk space allocated to Pagefile.

Windows XP Professional can utilize up to 4GB of Physical RAM, and up to 4GB
of Pagefile. Meaning that you can have no more than 4GB of each, but having
4GB of physical RAM doesn't mean you lose 2GB to pagefile.

As far as debugging, it doesn't actually run actively in the background, and
as far as processes and applications, that pretty much varies with the
configuration of the computer hardware and operating system settings, and
what applications you have running. Naturally, the more RAM that you have in
a System, the more that processes and apps will utilize. But that doesn't
mean that if you have 128MB of RAM, and Word uses 25% (or 32MB) of it, that
it will take 25% of your RAM when you upgrade to 4GB of memory.

Honestly, the more memory you can stuff in your system, the better. As long
as it doesn't exceed that 4GB threshold for XP.

Hope this helps!

Best Regards,

~Will

 

[Zv_oDD]

Thanx for the reply Will.
It explained alot of things very well and really clarified somethings
for me.

-Zv

 

[Guest]

Anytime!

 

[Ron Martell]

I have been reading around the web and everybody is saying that Windows
XP(non 64bit) Supports up to 4GB of "memory". But this isn't very
specific. Rumor has it at the IT department I work at that XP will only
be able to make use of 2GB of physical RAM and that the page file is
counted as the other 2gb 'memory'. Even though windows cant use the
page file like RAM, it has to dump large sections in and out of
physical memory (or so i am told).

The 2 gb physical plus 2 gp page file rumor is actually derived from
the 9x versions of Windows (95/98/Me) where this in fact was the
limitation.

Windows XP limits are as described by William Anderson.

Good luck

Ron Martell Duncan B.C. Canada
--
Microsoft MVP (1997 - 2006)
On-Line Help Computer Service
http://onlinehelp.bc.ca

"Anyone who thinks that they are too small to make a difference
has never been in bed with a mosquito."

 

[Ron Martell]

Honestly, the more memory you can stuff in your system, the better. As long
as it doesn't exceed that 4GB threshold for XP.

That part is not quite correct. Adding more memory can noticeably
improve performance only if the added memory results in reduced usage
of the virtual memory paging file. Therefore if the paging file is
not currently being used to any significant extent then adding more
memory will not provide a significant improvement.

Unfortunately there is no ready way of determing actual paging file
usage provided with Windows XP - it does not have an equivalent to the
'Memory Manager - Swap File In Use" reporting provided by the System
Monitor utility in Windows 95/98/Me.

There is a free utility that you can download and run which will
provide this information for you. It was written by MVP Bill James and
you can get if from
http://www.dougknox.com/xp/utils/xp_pagefilemon.htm or from
http://billsway.com/notes_public/WinXP_Tweaks/

If that utility shows actual page file usage of 50 mb or more on a
regular basis then that is indicative of fairly significant paging
file activity. Adding more RAM will reduce or even eliminate entirely
this activity thereby improving performance.

This apples regardless of how much or how little RAM is currently
installed in the computer, at least up to the 4 gb RAM maximum for
Windows XP.

Hope this clarifies the situation.

Ron Martell Duncan B.C. Canada
--
Microsoft MVP (1997 - 2006)
On-Line Help Computer Service
http://onlinehelp.bc.ca

"Anyone who thinks that they are too small to make a difference
has never been in bed with a mosquito."

 

[Guest]

Thanks for that clarification Ron.

However, in my experience, Windows 98 enjoyed bluescreening if you put more
than 512 into it...is that something different?

Best Regards,

~Will

 

[Ron Martell]

Thanks for that clarification Ron.

However, in my experience, Windows 98 enjoyed bluescreening if you put more
than 512 into it...is that something different?

The 9x versions of Windows did have issues with more than 512 mb of
RAM. There were actually two different types of problems that could
and did occur:

1. False "out of memory" type error messages caused by Windows
mapping an excessively large amount of RAM for use a disk cache,
thereby creating a shortage of address space for other functions that
also used the same 1 gb segment of address space allocated for these
system support type functions (AGP arpeture is another big user of
address space in this same segment.

This problem can be quite easily overcome by limiting the maximum size
of the disk cache. This is done by inserting a line into the
[vcache] section of the system.ini file that reads:

MaxFileCache=524288

or easier to remember

MaxFileCache=512000


2. There are also hardware related issues, the precise cause of which
has never been identified, which can arise on systems with RAM amounts
over 512 mb. These errors are uncommon at 512 mb, quite frequent at 1
gb, and always happen at 1.5 gb if they don't happen sooner. I have
never seen or heard of an instance where Windows 95/98/Me has ever
been successfully used on a computer with more than 1.5 gb of RAM
installed unless the MaxPhysPage parameter was in place.

Where it is necessary or desirable to have more than 1.5 gb of RAM
installed, such as a computer that is multibooting Windows 98 and
Windows XP then the work around is to add a MaxPhysPage parameter to
the [386enh] section of the system.ini file so as to prevent Windows
98 from attempting to use all of the RAM.

MaxPhysPage=40000 will limit Windows 9x versions to 1 gb of RAM.


Hope this explains the situation.

Good luck

Ron Martell Duncan B.C. Canada
--
Microsoft MVP (1997 - 2006)
On-Line Help Computer Service
http://onlinehelp.bc.ca

"Anyone who thinks that they are too small to make a difference
has never been in bed with a mosquito."

 

[Guest]

Right, so if my page file usage is more than 50MB regularly (currently 60MB)
I should increase my RAM, currently running 512MB on a laptop, should I
consider upgrading (not that I can afford it) or is it just a laptop thing?

Andrew.

 

[Bob Willard]

Right, so if my page file usage is more than 50MB regularly (currently 60MB)
I should increase my RAM, currently running 512MB on a laptop, should I
consider upgrading (not that I can afford it) or is it just a laptop thing?

Andrew.


:

No, it is not "just a laptop thing". XP has the same memory management
mechanisms for all PCs.

 

[Ron Martell]

Right, so if my page file usage is more than 50MB regularly (currently 60MB)
I should increase my RAM, currently running 512MB on a laptop, should I
consider upgrading (not that I can afford it) or is it just a laptop thing?

Andrew.

If that is the actual usage as reported by Bill James' utility then
you are at the point where more RAM is going to be of some benefit,
although the improvement would probably not be apparent except to
timed benchmark tests.

If the actual usage continues to increase (because of updated or
additional applications, etc) then the potential benefit of a RAM
upgrade will also increase.

Good luck

Ron Martell Duncan B.C. Canada
--
Microsoft MVP (1997 - 2006)
On-Line Help Computer Service
http://onlinehelp.bc.ca

"Anyone who thinks that they are too small to make a difference
has never been in bed with a mosquito."