How to Recognise ALL your RAM in Windows 7 64 BIT

  User-312386 20:35 15 Dec 2009

Hi guys

I have had problems with my Windows 7 64bit to recognise the full compliment of 4GB of RAM that i have! However, i have solved it and i wanted to give anyone the tip on how to to enable all your ram available!

OK first click start and then type msconfig in the search. Next click the Boot option and then the advanced options. Now tick the box that says Maximum memory and click ok apply ok. Now reboot the machine!

If the above does not work then you will need to enable memory mapping in the BIOS - To do this enter the BIOS(usually tapping delete key) on start up. Now look in the Advanced Chipset Features for "Memory Hole for PCI MMIO" and enable it! Now save changes and restart!

When you have restarted, see if you have the maximum memory, if you have have less then you need to go back into the msconfig options and untick the maximum memory box as advised in my first solution!



  gengiscant 11:02 16 Dec 2009

This tip will come in useful once I take delivery of 6gb ram.Thanks.

  CurlyWhirly 00:15 19 Dec 2009

Thanks but I *did* notice that MSCONFIG option before but it didn't work :(

I think it could be because my motherboard chipset has a 4 GB maximum memory limit

click here

I did try looking for the "Memory hole for PCI MMIO" option but couldn't see it :(

On my old Gigabyte mobo, there was a secret BIOS menu which was accessed by a combination of keys being pressed but I don't know if my current mobo even has a hidden menu that contains the "Memory hole" option ?

  User-312386 20:28 20 Dec 2009

Look in advanced setting on your BIOS and its called Memory hole at 15M-16M. Page 33 of your manual

  Eargasm 22:13 20 Dec 2009

Superb info madboy33©® !

I have 4GB installed but the system was showing 3.19GB useable, after applying the msconfig fix the system only showed 3GB useable however the BIOS fix worked a treat and the system is now showing the full 4GB, THANKS for sharing!

  User-312386 22:16 20 Dec 2009

No problem - But be careful as if you have the full 4Gb compliment, then no space is alloacated to hardware such as PCI-E cards, PCI cards and grpahics. There is a down side, but if your computer/Ram/Bus can handle it then go for it

  CurlyWhirly 09:30 21 Dec 2009

Ah that option.

I did try that but it didn't work probably because in the manual it says that this memory space is reserved for ISA expansion cards and I don't have one of these as they are obsolete now I think?

I have 4 GB of RAM installed but only 2557 is available to Windows.

I can change this to a lower figure but not a higher figure.

click here

I 'lose' around 1.5 GB and I don't understand why my graphics card reserves a GB of system RAM when it has 512 MB of dedicated video memory (I have a NVIDIA GeForce 9800 GTX+ )

click here

In any case, as you pointed out to Eargasm, if the fix 'had' worked for me, my PCI Express graphics card might suffer a performance hit and as I'm into PC gaming, I wouldn't want that ;)

  User-312386 18:27 21 Dec 2009

You would notice the "performance hit" straight away, as all the allocation would be used up straight away

  mudplug 16:55 06 Jan 2010


I'm having pretty much the same problem. I have 4GB of ram installed, as well as an Nvidia Geforce GT240 with 1GB of RAM. My system is showing that I have 4GB of RAM (Win 7 64 bit), but only 2.5GB is available.

According to system info in my display controls, I have 1150 MB of shared system memory. In DXdiag, it says I have 2136 MB of video memory (Approx.).

How in the heck do I get this back for regular system use? I have a foxconn mobo (G31MX) and I've tried the msconfig trick as well as the BIOS settings (Memory hole at 15M-16M is enabled). Nothing I've done so far has worked to get back that damned 1.5GB of RAM!

Anyone have any suggestions? I'm at my wit's end here.

  DieSse 19:27 06 Jan 2010

The intel G31 chipset can only generate 4GB of addresses. Since a chunk of them are lost to hardware in the system (apart from graphics) you could only ever get 3 - 3.5 GB under any circumstances.

click here

On the graphics front, it appears your card has 1GB, plus it is using another 1GB (approx) of system RAM. I presume the nvidia driver is where you control how much shared RAM you allocate.

  DieSse 19:31 06 Jan 2010

It might also be that the BIOS is where shared graphics RAM is allocated - so if you can't find it in the nvidia driver, look in the BIOS.

Is there any chance that your motherboard has on-board graphics (that you are not using), and shared RAM is allocated to that?

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