4GB RAM on Dell GX280 showing only 3GB RAM

[Guest]

I have recently upgraded my Dell GX280, running Windows XP Professional with
Service Pack 2 and fully patched, from 2GB of RAM to 4GB of RAM to
accommodate using two Virtual PC Servers (each assigned 1GB of RAM) and my
SQL Server 2000 instance (assigned 1GB of RAM). I do not have a single
application that's trying to access more than 2GB of RAM, so I don't need to
use the LARGEADDRESSAWARE flag. I have tried to use the /3GB flag for my
boot.ini but that prevents the OS from starting completely. I get a logon
screen but it sits there after trying to logon to the domain. I do not have
a pagefile so that I don't go above the 4096 MB Virtual Memory ceiling and it
still doesn't completely register 4GB of RAM in both the System Properies or
the Task Manager. My BIOS is on the latest version, A07, and it does
recognize the 4GB of RAM, as does System Information within Windows XP. So
that leads me to a couple of questions:

1) Does anyone have any ideas on how to get Windows XP Professional to see
all 4GB of RAM properly?
2) If your response is the /3GB switch in the boot.ini file, does anyone
know why the OS doesn't load completely when I do apply it?

I've been racking my brains and Google for answers to no avail. Any help
will be truly appreciated. Thank you in advance.

 

[Guest]

have to tryed to reset your bios to default setings and check with dell that
you motherboard will take 4 gigs of ram also make sure every stick of ram is
working take one out and turn the pc on check the bios and not what it says
repeat until you only have one stick of ram instaled

 

[Jerry]

Maybe here: KB316739 - How to Use the -USERVA Switch in the Boot_ini File to
Tune -3GB Configurations

or here: KB291988 A description of the 4 GB RAM Tuning feature and the
Physical Address Extension switch

or here: KB833721 Available switch options for the Windows XP and the
Windows Server 2003 Boot_ini files

or here: Memory Support and Windows Operating Systems (Microsoft WHDC
article)

or here: Sysinternals Freeware - BOOT_INI Reference at www.sysinternals.com

or here: KB888855 The System tool and Task Manager do not display 4 GB of
RAM in Windows Server 2003 and in Windows XP

 

[Mak]

Laurence,
you're confused largely on virtual and physical memory under XP-32bit.
First on physical - WinXP is licensed, capped (artificially) at 4GiB, no
matter how much RAM you install, the barrier is 4GiB. It is not 32-bit
platform limitation, for example with /PAE certain 32-bit Windows server
platforms can see and use up to 64GiB of RAM.
To why you can't see 4GiB of RAM under XP - last GiB is reserved for PCI
devices, the more devices you have, the less RAM you will see. Under server
[when / if your motherboard / BIOS allow you to re-map (memory hole)
reserved addresses to above 4GiB. Play with your BIOS, see if you can, by
enabling memory hole get OS to see few hundreds MiB more of your RAM] you
can most of the time see full 4 (or more) GiB of RAM, server PCI drivers
also should have no problems (as they are generally better) locating those
addresses.
Basically, the answer is: no, you can't see 4GiB of RAM under XP-32bit, and
the fault is not XP, I blame drivers that expect to find devices at below
4GiB barrier. Windows XP just enforces what is already a fact.

Virtual memory.
/3GB switch does NOT affect RAM. It affects how 4GiB of virtual memory per
process is split between system and user modes.
Applications do not think in terms of RAM, nor they can address RAM directly
(i.e. bypass Windows VM manager).
Applications use virtual memory. Each application (correct term here will be
process), is guarantied 2GiB of virtual address space (default) and 3GiB
when /3GB switch is used. Only when application is coded with
LARGEADDRESSAWARE flag, application can use 3GiB of virtual memory. Number
of processes running and their demand (more important than a number) for
memory creates total virtual memory in use.
It doesn't matter how much or how little RAM you have, virtual memory
addresses do not rely on that.
Playing with /3GB switch will do nothing to inability to see 4GiB of RAM
problem.

You are also confused on Paging file.
Like a tree is not a forest, paging file is not a virtual memory, but only
one of the files VM manager uses to create virtual memory. It is a special
file, yes. It is used by Windows VM as a backup for process virtual private
address space.
The limitation for this file size wise is 4095MiB per partition (normally)
under 32-bit Windows. You can have up to 16 paging files.
Keeping in mind that paging file is not virtual memory, there is no hard
limit to what virtual memory usage will be on your system.

To see how much virtual memory is in use at this point in time, use Perfmon
| Process | virtual bytes | _total.
To see how much of that is actually in paging file - Perfmon | Paging File |
%Usage | _total.

If you disable paging file (like you did) you just cripple your system,
whatever private bytes can be paged out, due to memory demand, must now stay
paged in and other stuff will be paged out.
Enable your paging file.

To be able to see 4GiB of RAM you have 2 choices:
use XP 64-bit as a host
use WIndows Server OS as a host