4x1GB = 2688mb? odd problem

By philldmc ·
I have a ASUS P5GV-MX motherboard with a P4 3.0Ghz, for the longest time I've been running 2GB of memory 2x1GB = 2048mb which is reported by bios.

I was going to upgrade to Win7 so I purchased two memory sticks, exact matches, Kingston DDR400 2.6V, I can run any two in any combination without any problem.

The problem is if I add 1 or 2 additional sticks the memory reads in the bios as 2688mb regardless if it is 3x1GB or 4x1GB. Once I removed the ATI 2600 Pro PCIe and use the onboard video the system memory increased to 2936mb, again didn't matter if I was running 3 or 4 sticks.

When I run 3 sticks the system reports single channel mode, if I run 4 sticks the system reports dual channel mode.

I can mix and match any of four in any of slots and system runs at 2048 just fine..it is when I add 3 or more sticks. As of now there is no OS on the system this is all reported by the bios. I even reset the bios by jumper, confirmed all settings, etc

Any suggestions? On a side note, tested all memory, all memory reported fine on different system.

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RE:4x1GB = 2688mb? odd problem

by ameack In reply to 4x1GB = 2688mb? odd probl ...

Is this the part number for the RAM KHX3200AK2/2G

Also Each memory slot can hold DDR PC2700,DDR PC3200 with a maximum of 1GB per slot

Make sure that Your system does not support ECC. Because ECC and non-ECC modules should not be mixed within a system, install the same type of modules that are already in your system.

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Non-ecc Kingston DDR400/1G

by philldmc In reply to RE:4x1GB = 2688mb? odd pr ...

All four sticks are same make and model,

Kingston DDR400/1G 2.6v

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Check in BIOS setup.

by seanferd In reply to Non-ecc Kingston DDR400/1 ...

BIOS may be detecting the RAM, but not using it correctly. Check any memory config you can find.

Does it display the full 4 Gb or whatever in POST?

Yes, you need balanced sets of sticks for the board to use dual channel mode.

You need a 64-bit OS to see anything larger than 3.25 Gb RAM. It will be less if you use onboard video. Also, the Asus mobo would need to be 64-bit (which it is).

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have a read of this

by .Martin. In reply to 4x1GB = 2688mb? odd probl ...


in you case it is a bit worse than the normal, but I don't there is anything you can do

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No OS installed all reading from bios/cmos

by philldmc In reply to 4x1GB = 2688mb? odd probl ...

Please note, all memory modules are exactly the same each stick is Kingston DDR400/1G v2.6, model number 9905193-109.A01LF, they are all exactly the same. Each one has been tested using mem86+ and MS Memdiag, all test good.

I can put in the memory in any combination of any two memory sticks and I will get 2048GB of memory, with add in video card, and 2040 with onboard video card.

When I go to add a thrid stick of memory the bios reports the memory as 2688, regardless of memory configuration with three or four sticks, 3 x 1GB or 4 x 1GB, it always reads 2688mb.

However, if I remove the PCIe and run off the onboard video the memory reports as 2936mb, regardless if it is 3x1GB or 4x1GB.

Various configuration I've tried:

If I place memory into slot 1 (closest to the CPU) the bios reads Single channel mode at 1024mb

If I place memory into slots 1,2 the bios reads Single Channel Mode at 2048mb

If I place memory into slots 1,3 or 2,4 the bios reads, Dual Channel Interleave at 2048mb

If I place memory in slots 1,2,3 the bios reports Dual Channel Asymmetric at 2688mb

If I place memory in slots 1,2,3,4 the bios reads Dual Channel Interleaved at 2688mb

I have reset the bios to factory default and updated to the latest bios (which is dated 2006)

I'm starting to lean that this is a bad board, never knew it until I needed to add more memory. I did send off an email to ASUS. I will post their response.

My next step is to pull 4 1GB Cosire and see how they work.

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Sounds like the board, then.

by seanferd In reply to No OS installed all readi ...

If each stick tests out at 1 Gb, something else is wrong.

Best of luck getting this resolved with Asus.

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In the BIOS ......

by Peconet Tietokoneet In reply to 4x1GB = 2688mb? odd probl ...

Go into the BIOS and select "Load default settings" then "Save and Exit", this should re-flush the system to make it see your full 4 gb memory.
Once it has seen your memory correctly go into the BIOS again and set up your own boot configuration. Also make sure you have not overclocked the system, hence the "Load default settings".
See if this helps:

Make sure your BIOS settings is set up as "Load default setting".

1. Put in one stick of memory in slot Dimm A1 (Slot 1, first slot from the processor).
Reboot, then check the rating for the memory.

2. Put in the second memory in Dimm B1 (slot 3, third slot from the processor).
Reboot, then check the rating for the memory.

3. Put the other two lots of memory in the other slots, then again select "Load default settings", then "Save and Exit", now when you boot into your BIOS you should have well over 4gb (4096) of memory installed (each 1gb of memory is listed as "1024" x 4).

Remember to always put memory in PAIRS

If that does not fix your problem then you could try and downgrade the BIOS to "P5GV-MX BIOS 0501", but for this you should only have ONE stick of memory in "DIMM A1" slot.
When you have downgraded the BIOS (and check it) then fully shutdown your computer.
Now get hold of your BIOS update "P5GV-MX BIOS 0801" and load it.
When you have updated the BIOS (and check it) do a full shutdown.

First..memory into slot DIMM A1
Second.memory into slot DIMM B1
Third..memory into slot DIMM A2
Forth..memory into slot DIMM B2

Now go into your BIOS and select "load default settings".

Hopefully this should get your motherboard to see your additional memory.

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Thanks for the reply

by philldmc In reply to In the BIOS ......

I've tried everything except to downgrade the bios and then upgrade. The problem was with the original bios that came with the board. I updated to 0801 to see if that fixed the issue.

I used the jumper method several times to reset the bios, to load default settings.

The one thing I find interesting is, if I use a PCIe video card with 3 or 4 memory sticks the memory reads 2688mb. If I remove the video card and use the onboard video card the system memory reads 2936mb.

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For any BIOS updates or downgrades just take out the graphic card..

by Peconet Tietokoneet In reply to Thanks for the reply

Just take out the graphic card and use the on-board graphics to iron out the problems. Downgrade first and then run the update for your BIOS as in my earlier post.

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Usable Versus Physical RAM

by TheChas In reply to 4x1GB = 2688mb? odd probl ...

I presume that you are running Windows XP and it reports the same amount of RAM that your BIOS reports.

Of interest, if you upgrade to Windows Vista with SP1 or Windows 7, Windows will by default report the installed RAM and not the usable RAM.

With a 32 bit motherboard and a 32 bit operating system, there is a maximum address limit of 4GB of RAM. However, NO 32 bit system can actually address and use all of the 4 GB of address space for system RAM.

At a minimum, the upper 750 MB of RAM address space is used for system overhead tasks. This includes the address space for the PCI bus and your video card. Thus, the most usable RAM on ANY 32 bit system is 3.25 GB.

While the 2.68 GB you see with your video card installed is on the low end, the fact that you get around 400 MB of RAM back when you remove your video card just confirms that you have a lot of system overhead that uses up RAM address space.

While a BIOS update "might" report the full 4 GB you have installed, you will never have use of the full 4 GB of RAM with a 32 bit motherboard and 32 bit Operating System.

The only way to have more usable RAM than the 2.68 GB you see is to upgrade to a 64 bit motherboard and CPU AND install the 64 bit version of Windows 7.

Even if you upgrade to 64 bit hardware, the 32 bit version of Windows will still limit you to no more than 3.25 GB of usable RAM.


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