Hi Carey,

Thanks for you help. I tried what you recommended but to
no avail. Nothing changed at all with respect to my
original post. When System Information (and Task Manager
for that matter) display the total physical memory, is it
read from the BIOS or does it have it's own method of
determining what the physical memory amount is? Does XP
see a dual-channel pair as a single DIMM? Is there
another way I can test/tell whether all 4GB are actually
going to be used by the system?

If anyone else has an answer or suggestion please feel
free to post.

Thanks,

Eddie



-----Original Message-----
How to Use the /USERVA Switch in the Boot.ini File to
Tune /3GB Configurations
http://support.microsoft.com/default.aspx?scid=kb;EN-
US;316739

Correct your boot.ini file:

[boot loader]
timeout=30
default=multi(0)disk(0)rdisk(0)partition(1)\WINDO WS
[operating systems]
multi(0)disk(0)rdisk(0)partition(1)\WINDOWS="Micr osoft
Windows XP Professional" /fastdetect /3GB /Userva=2900

Windows XP SP1 May Not Start with the /3GB or /USERVA
Switch
http://support.microsoft.com/default.aspx?scid=kb;en-
us;328269&Product=winxp

"Stop" Error Message When You Start Windows XP by Using
the /3GB Switch
http://support.microsoft.com/default.aspx?scid=kb;en-
us;829364&Product=winxp

--
Carey Frisch
Microsoft MVP
Windows XP - Shell/User

Be Smart! Protect your PC!
http://www.microsoft.com/security/protect/

---------------------------------------------------------
--------------------------

"Eddie" wrote in
message:
...

| Hi Everyone,
|
| I have an Athlon Fx-53 (939) system with 4GB of dual-
| channel memory filling the memory banks of an Asus A8V
| motherboard.
|
| For some reason XP doesn't seem to detect the full 4GB
of
| memory installed. In the System Information tool it
| claims a "Total Physical Memory 2048.00MB"
and "Available
| Physical Memory of 2.64GB", which is incorrect (not to
| mention seemingly illogical).
|
| The system's BIOS, drivers, and windows patches have
all
| been updated. I've checked the memory settings in the
| BIOS and the only setting that seemed to be relevant
(the
| others were all related to timings and bank/node
| interleaving) was the "4GB mapping" setting, which I
| toggled between enabled and disabled and got different
| but incorrect results (with it disabled System
| Information claimed a "Total Physical Memory
2048.00MB"
| and "Available Physical Memory of 3.16GB", with it
| enabled it was as above).
|
| I have also installed the XP 64-bit beta and it
returns
| similar, yet different again, results. With the 4GB
| mapping enabled, System Information claimed a "Total
| Physical Memory 2048.00MB" and "Available Physical
Memory
| of 3.28GB", while disabled it claimed a "Total
Physical
| Memory 2048.00MB" and "Available Physical Memory of
| 2.85GB" -- very strange results.
|
| What makes these results even more strange is that the
| BIOS claims 4096MB of memory, the CPU-Z application
| claims 4 DIMMS of 1GB, SiSoft Sandra's System Summary
| tool claims 4096MB of total memory. Also, Windows
Task
| Manager claims a total physical memory of 3144948
bytes
| and an available physical memory of 2769732
bytes...very
| strange.
|
| Perhaps Windows views a dual-channel pair as a single
| DIMM? If so, why does it say there is 3.16GB of
| available physical memory?
|
| To be honest, it matters little what all these tools
| report. What I'm concerned with is whether the system
| actually has access to all four GB and how I can
ensure
| this is the case. This system is intended to run
| scientific simulations and all four GB of memory are
very
| necessary. Any help would be greatly appreciated.
|
| Thanks,
|
| Eddie
.