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4 gigs installed, windows only sees 1.48

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November 5, 2008 3:39:11 AM

ive got corsair CMX1024-3200C2 SDRAM, three 1 gig modules total. my motherboard is an ASUS A8N32-SLI Deluxe and im running windows XP pro 32-bit service pack 3.

my problem is that if ive got anything more than 1 gig of memory installed windows will only register 1.48 gigs. thats the amount listed in the system info via control panel and it is further verified by viewing my performance tab in the task manager. additionally, when running 3dMark06 my system is detected as having about 1.5 gigs of ram

ive tried running all 4 modules, two of them, and only one of them. in all cases initial memory check during start up will list the correct amounts installed and amount OK. i had to enable the memory hole in bios to acheive this but that much is fine. i know that the memory eaten up by the OS is taken into account when windows lists available memory but im missing entirely too much here.

i cant find any settings within XP that aloow me to tweak my available memory. the closest i can find is focusing memory allocation for either programs or system cache, and i know that wont fix my problem.

i see a lot of similar threads on this forum from people who are having trouble hitting the 4 gig cap in XP 32 bit but all of those cases ive seen have had a distinctly higher available memory count than i do now, even those who are running 2 gigs.

im stumped now, i cant even optimize with 2 gigs when everything seems to suggest i should be able to. so i hope someone has some wisdom theyd be willing to share that could help me out of this.
November 5, 2008 4:31:08 AM

have you taken the VGA into account yet? What's your VGA memory?
a b } Memory
November 5, 2008 7:39:57 AM

That would only be an issue down to around 2.7GB max.... unless you happen to be running a couple 1Gb cards spearately, so as to run multiple monitors...

Here's a simple explanation:
Your 32-bit XP has a total of 4GB of memory addresses to use. That's all it can assign. Some or most of your devices, including multiple parts of your motherboard, your video card memory, and more, require addresses.

Picture several city blocks. Some buildings will take up a big portion of addresses, while others don't need so much.

Once XP hands out those addresses, it has X amount left to use. For normal systems, this amount will likely be around 3.4GB. If there is only 2GB of system memory installed, XP should use it all.

The problem probably lies, in your case, in the BIOS. Perhaps you are forcing dual channel somehow, effectively excluding the third stick from playing with the other two.
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a b } Memory
November 5, 2008 8:04:39 AM

Are you running a 4870x2 or dual GTS 280's?
If so, you are eating 2Gb of the 4Gb available addressing space up with just the GPU's.
Try testing each stick/slot with memtest.
There is the possibility that your older hardware is just wore out and starting to fail.
Have you tried booting into a x86 distro of Linux and looking at the available RAM from there?
November 5, 2008 8:06:14 AM

^Most Likely
a b } Memory
November 5, 2008 9:56:54 AM

The 4 gig of memory Windows 32 bit can address includes ALL the memory in your system. You have to take into account the memory on your hard drives, motherboard, Cache memory on your processor, sound card or on board sound, any other add in cards, and your video card. Add all that up, and subtract it from 4 gig. All your devices with memory will be assigned memory address space FIRST, then whatever is left over, up to the 4 gig mark is assigned to RAM. If you have a video card with 2 gig of memory, then you would only have about 1.5 gig left for RAM.
November 5, 2008 11:51:07 AM

Wow, 4 Gigs of Ram, and Windows only sees 1.48 Gigs...

What the heck are you guys doing to these poor computers? :pt1cable:  :pt1cable: 

AJ
November 5, 2008 1:15:28 PM

Cards like the 4870X2 can destroy 32-bit systems in this way; half your memory dies with that card by itself.

I was starting to wonder when we would get a post like this too :D 
November 6, 2008 2:01:12 AM

i am running two nvidia 8600's at 512 each in SLI mode. so it would seem that they should only be eating up 1 gig at the most. however, ive tried removing one of them to see if my situation improved but no luck.

hard drive, ive got a single 70 WD raptor but i dont know what sort of memory that would chew up. ive never even heard of a hard drive taxing the memory in such a way.

processor is a Athlon 64 X2 4600+ so the cache memory there isnt too much.

Sound blaster audigy for a soundcard but again, not much to that either.

thats basicly it for devices on the computer. assuming that the video cards are eating up a gig of the ram id still be about 1.5 gigs under 4.

is there some kind of utility i can use to see where windows is assigning all of my memory?

November 6, 2008 4:26:32 PM

If its only 1GB being used by the GFX cards, then something is probably wrong with the RAM then. Try running memtest on each stick individually, and check the BIOS to see the size each stick is detected as.
a b } Memory
November 6, 2008 5:58:44 PM

Either MAXMEM is set in boot.ini advanced options or you have S/W or H/W memory remapping enabled in BIOS.

Open System Configuration Utility (Start > Run > msconfig), click on the BOOT.INI tab along the top, open Advanced Options, uncheck the box next to /MAXMEM (if present), then click OK or Apply before exiting. Now enter BIOS Setup, locate S/W and H/W memory remapping options, make sure both are set to DISABLE, Save Changes and Exit.

One of those is most likely the problem. If not, let us know.
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