6Gb Ram - 3.25Gb Usable

Hey Guys basically i replaced my mobo and installed 6GB ram
However i only get 3.25 usable.

Before i changed my mobo since it was faulty i had 4GB ram which ran all 4GB ram.
Adding the 2GB total 6GB only allow me to use 3.25GB ram
Taking 2GB total 4GB ram allow me to use 2GB ram.

I don't know why!!

I currently have 6GB ram installed.

In bios it says 4024mb , Windows say i have 6GB (3.25GB usable)


What bit OS?

Sorry forgot to post about OS xD
Win7 64Bit

Either the OS is 32-bit or the computer does not support 64-bit because 32 will 'cap out' @ 3.25 but, 64 will not.


Seriously it does support 65bit!
I had 4GB ram installed before and 4GB all usable

but when i replaced my mobo for the same one it says 3.25GB usable now on 6GB ram
Which i installed 2 more Ram

Same M/B?? Sorry, now I'm stumped. I would look @ the sticks themselves as the possible issue. Either they are not all good or not all the same or not plugged in well enough.


They are all the same. 2GB by 3 sticks
Same brand.

No issue as i ran memtest

but Bios says its 4GB and windows says 6GB.
3.25 usable overall.

Tried to make this simpliest as possible..

Side story
When i had 4GB installed 4GB was usable untill i changed the motherboard.
motherboard is the same brand and version.
replaced as a ram slot was faulty.

Now since then i been getting 3.25GB usable.

Understand now?

Last edited:


Extraordinary Member
Right, what to do.

Go into Bios, Advanced, Chipset Configuration, set Memory Remap Feature to enabled.

£50 please. :D

my Mobo: MSI 870A-G46
Does not have Memory remap in bios.
Would of done that but don't have it


Extraordinary Member
Owe you £50 then. Strange, not seen a bios without remap but we live and learn.


Noob Whisperer
Just wondering if there is something about dual channel mode and the fact that you are using 3 memory stick that has something messed up. Page 22 of your mother board manual suggest how to populate the memory slots in respect to dual channel memory mode.
Have you checked if you return the system to 4 gigs of memory in slots 1 and 2, does it recognize the full 4 gigs of memory?

Well its Single Channel now as there is 3 sticks.
Before when i had Dual Channel with 2 Sticks.
Still the same. 2Gb usable.


Windows Forum Admin
Staff member
Premium Supporter
Your problem is honestly one of the strangest on record. Please ensure you are not running a 32-bit operating system. To do this, try opening a command prompt by going to:

Start -> Search -> cmd

In the command console type "systeminfo" and press enter. Scroll up to find:

"System Type: x64-based PC"

(While there are other ways to obtain this information, this would seem to be a quick and reliable way).

I would recommend, also, going into System Information, by going to Start -> Search -> msinfo32.exe

If you are comfortable revealing system information, export your information as a text file and attach it to a post in this thread. The information in this file will contain what Windows recognizes on your system a fairly fine degree, but will not compromise security information such as the product keys, etc.

I would also recommend that, during this process, you identify whether or not your OS is picking up on all of the memory modules. A good system diagnostics and reporting software is AIDA64: Downloads | AIDA64

You can use a 30 day trial just to collect as much information as possible on what could be the cause of this problem. However, memory allocation in Windows 7 64-bit should not be the cause of the problem. It is much more likely that a severe misidentification of some component is the cause (i.e. human error). All of this is conjecture right now, because, quite honestly, without identifying the cause, that is always a likely culprit.

I would go so far as to suggest that you really do follow these steps, if only for your own benefit, and to get to the bottom of this problem. Again, this problem is mostly seen on 32-bit systems that are trying to utilize >4GB of RAM. In that instance, Windows can never allocate more than 4GB, and a certain amount of RAM, usually .5-.75GB under the 4GB hard limit, is reserved for allocation of graphics card memory. If you are using 64-bit Windows, you should not have any reserve memory allocation problem.

If you can completely rule out that you are using 32-bit Windows, this looks like a hardware problem. DIMM slots could even be damaged or have something in the slots blocking contact with the modules. Carefully check for hardware errors by removing the memory after fully powering down and disconnecting the system. Sometimes, on rare occasions, when installing new DIMMs, you may encounter a problem whereas if power is not fully drained from the board, or if there is an electrical discharge when installing the memory, the DIMM slots or RAM can be damaged beyond repair. To rule out a problem in this area after a hardware inspection, you're going to want to create a Memtest bootdisc and test your RAM. See also: Memtest86+ - Advanced Memory Diagnostic Tool

If you come to believe that one of the DIMM slots or RAM modules may be damaged, you should start cycling memory, one-by-one, into various configurations on the motherboard. This is best done by testing each RAM module on DIMM SLOT 1 and DIMM SLOT 3 (for tri-channel configurations) after first testing all modules on DIMM1. Go ahead and slowly expand until you have all of your RAM slots occupied once again and have ruled out any damage to each module. Eventually, you may discover a problem with one of the DIMMs.

My main problem with this solution itself, however, is that the memory is posting. The reason why the operating system may not be able to recognize more than 3.25GB still eludes me, but there have been occasions whereas when a DIMM slot itself was damaged, I found that Windows would recognize all of the memory, but only show some available. In fact, one DIMM slot on a tri-channel board may still be reporting, with another one damaged. This would explain why, if you have 2x2x2, you see 4GB and the OS cannot allocate >3.25GB. While this is a long shot, it is a situation I have seen play out before, sometimes with 16GB reported and only 8GB or 4GB usable. The fact that it is "3.25GB" still eludes me.

Try all of these steps, but for the most part, extensive testing is going to be required to resolve this problem. Unless of course you are running 32-bit Windows. My opinion would be, based on all information presented, that this is a partial motherboard failure that may have taken place when you installed the additional RAM or a problem with the RAM itself. Try to remember if you banged or dropped the RAM before installing it, or if any questionable incident may have taken place that may have fried any of the components.

Any further information you can provide will be useful in moving forward. It would be especially useful if you post on the issue if you have already managed to resolve it somehow.

Last edited by a moderator:
1) "System Type: x64-based PC"

OS Name Microsoft Windows 7 Ultimate
Version 6.1.7601 Service Pack 1 Build 7601
Other OS Description Not Available
OS Manufacturer Microsoft Corporation
System Name ANH-PC
System Manufacturer MSI
System Model MS-7599
System Type x64-based PC
Processor AMD Phenom(tm) II X6 1045T Processor, 2700 Mhz, 6 Core(s), 6 Logical Processor(s)
BIOS Version/Date American Megatrends Inc. V17.16, 28/11/2011
SMBIOS Version 2.6
Windows Directory C:\Windows
System Directory C:\Windows\system32
Boot Device \Device\HarddiskVolume2
Locale United Kingdom
Hardware Abstraction Layer Version = "6.1.7601.17514"
User Name Anh-PC\Anh
Time Zone GMT Standard Time
Installed Physical Memory (RAM) 6.00 GB
Total Physical Memory 3.25 GB
Available Physical Memory 1.37 GB
Total Virtual Memory 6.50 GB
Available Virtual Memory 3.67 GB
Page File Space 3.25 GB
Page File C:\pagefile.sys

3) Memtest is passed.

4)AIDA64 file is in attachtment



Windows Forum Admin
Staff member
Premium Supporter
You will not like the next steps, but they are the best logical conclusion:

If you can determine that all of the DIMM slots will post RAM in different configurations, the next step would be to swap out the RAM with replacement sticks. Find out if the new motherboard stick you just bought works independently of the others. If that is the case, time to look at the motherboard:

I would consider contacting the motherboard manufacturer with this specific problem and start to consider replacing the motherboard as a real possibility. Unless someone else has an idea, these are the steps I would take. :(

Am going to reinstall Win7 64bit
And see if all ram is usable
Il reply back with the results.

Don't like messing around inside the computer so il take this step first


Noob Whisperer
Did you or someone else or something set the maximum memory option under the boot tab -> Advanced options (button) of msconfig?
Click the start orb and type
and hit enter
select the boot tab
and click the Advanced options.... button
See what if anything is noted there regarding max memory?

There is (Mike eluded to this, also) some hardware issue, in this, involving the RAM sticks, the M/B or both. I will, also, re-enforce the fact that it is, indeed, a 'Best Practice' to treat RAM in pairs.

I, too, strongly suggest looking @ this w/ another M/B & a new set of RAM

Suggested possibilities:



Am Unable to install Win7 for some reason.
Am going to recheck each ram one by one tomorrow morning.

Will report back again.
i will go with the dual instead of single.

Did you or someone else or something set the maximum memory option under the boot tab -> Advanced options (button) of msconfig?
Click the start orb and type
and hit enter
select the boot tab
and click the Advanced options.... button
See what if anything is noted there regarding max memory?
Checked msconfig -.-
Seem the box was checked. I unchecked it now
And its giving me 4GB usable now out of 6GB :)
Thats a start.

Got to go college now. So i will check each ram serparately when i get back.

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