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Only 3072 MB of memory usable on Win 7 64 bit. HELP

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December 20, 2010 5:56:01 AM

Hi guys.

Today I noticed that my system is only using 3072mb of RAM, I have 4 GB in my system and they used to work pretty nice until now, before all 4 were usable, now Im missing 1. I thought this was because ram remap feature was diabled on the bios (BTW here's my board : Biostar G31 M7 TE). So I enabled it and rebooted my system. Turns out it's still the same... I tried also enabling the memory hole to 15-16 mb (the only setting appart from diables) same results. Can anyone help me please? I think this is decreasing my PC's performance...

edit: what seems to be doing this is the ''pci mmio allocation'' I googled this and didn't found a really explanatory definition... can someone help me with this so it doesn't takes ram from me? =(

a b $ Windows 7
December 20, 2010 7:24:40 AM

Sounds like shared memory for the on board graphics, id check bios settings and disable the onboard graphics if you have a separate card.
a b } Memory
a b $ Windows 7
December 20, 2010 7:39:38 AM

VGA onboard always use memory sharing with your RAM & clock control (integrated GPU used ). check in your Bios, how much your VGA & IGP use RAM ?
Related resources
a b } Memory
a b $ Windows 7
December 20, 2010 8:19:32 AM

You might want to check that you haven't set any RAM limit in msconfig.
December 20, 2010 3:37:28 PM

I checked RAM limit and it's setted to 0. I'm using a Radeon 5770. By accident while touching the BIOS I enabled the IGP and then turned it again to dedicated...

BTW:

in the integrated graphics pannel the following settings are avaliable :
PCI/ IGD
PCI/PEG
PEG/IGD
PEG/IGD
PEG/PCI


What one should I select?

I disabled ram remapping feature and RAM is up to 3326 MB...
a b $ Windows 7
December 20, 2010 8:26:01 PM

touching the BIOS.?
December 20, 2010 8:51:05 PM

verbalizer said:
touching the BIOS.?


tweaking*
a b $ Windows 7
December 20, 2010 9:05:02 PM

got it.
December 21, 2010 2:42:20 AM

BUMP
a b $ Windows 7
December 21, 2010 8:11:03 AM

i belive PEG im not 100% sure tho as i have not used intergrated GFX for many many years
a b } Memory
a b $ Windows 7
December 21, 2010 9:33:06 AM

LuigiVN said:

edit: what seems to be doing this is the ''pci mmio allocation'' I googled this and didn't found a really explanatory definition... can someone help me with this so it doesn't takes ram from me? =(



"PCI MMIO" means "Memory Mapped In/Out" for (some device) on your PCI buss. And, Yes, as opined earlier - Integrated Graphics can/do use system memory.

To see what's what, click your Start Icon, and type 'Resource' in the search box. Run the "Resource Monitor", and click on the 'Memory' tab.

Grey = Hardware reserved (nothing you can do about this, short of changing your hardware - when you changed back to Dedicated, are you sure you disabled the IGP??)

Orange = Modified (the system will have to write this to disc before this group could be free'd - normal to have some)

Blue = Standby (being used for Cache~ing - will be relatively low on start up, but Win 7 will gradually fill this with objects it thinks may become useful. This is normal behavior and has little/no impact on system performance)

Light Blue - Free (not being used at all. Please note is is desirable for Standby {blue} to be filled and the unused group to be small.)
December 21, 2010 6:06:42 PM

Scotteq said:
"PCI MMIO" means "Memory Mapped In/Out" for (some device) on your PCI buss. And, Yes, as opined earlier - Integrated Graphics can/do use system memory.

To see what's what, click your Start Icon, and type 'Resource' in the search box. Run the "Resource Monitor", and click on the 'Memory' tab.

Grey = Hardware reserved (nothing you can do about this, short of changing your hardware - when you changed back to Dedicated, are you sure you disabled the IGP??)

Orange = Modified (the system will have to write this to disc before this group could be free'd - normal to have some)

Blue = Standby (being used for Cache~ing - will be relatively low on start up, but Win 7 will gradually fill this with objects it thinks may become useful. This is normal behavior and has little/no impact on system performance)

Light Blue - Free (not being used at all. Please note is is desirable for Standby {blue} to be filled and the unused group to be small.)

The hardware reserved used to be 1 MB and it's now a whole GB... I tried settings my bios to defaullts and nothing happened...

edit: Is there a possibility my Video Card (5770) is using that memory? I recall reading something like RAm being used by the videocard to improve perfomance... How can I limit that to only the onboard 1 GB of GDDR5??? My resolution is tiny si 1GB is overkill (1280 x 720)
a b } Memory
a b $ Windows 7
December 21, 2010 7:46:34 PM

Only the aperature for the video card needs to be mapped - not the entire amount of video RAM. That varies depending on the card, but 256MB is a good upper limit.

I'll ask again: Are you *sure* you disabled the onboard graphics, and are you *sure* the 'Max Memory' setting is not checked in msconfig?
December 22, 2010 12:02:18 AM

I'm not sure, I'm currently using one of the DVI ports of my VC. but it could be enabled somehow. in the integrated graphics pannel the following settings are avaliable :
PCI/ IGD
PCI/PEG
PEG/IGD
PEG/IGD
PEG/PCI

Which one should I choose? Is there another setting in the BIOS i should normally be aware of in this case?

The max memory setting isnt checked in msconfig
a b } Memory
a b $ Windows 7
December 22, 2010 7:48:28 PM

The integrated graphics should be DISabled. If you enable them, they will consume system memory. This is likely the cause of your complaint.
December 24, 2010 11:04:11 PM

There isnt a setting like : Integrated graphics adapter: enables/ disabled. The only settings are the ones I mentioned up there

Merry Christmas
December 25, 2010 11:25:41 PM

Set it to PEG/PCI

PEG=PCIExpress
PCI=PCI
IGD=Integrated


That should fix your issues.
December 26, 2010 3:49:37 AM

Itd din't. My cousing told me to remove the DIMMs and then put them in again, i'll try that...
December 26, 2010 4:00:32 AM

Guys here's an interesting fact: When i boot only with 1 of my 2 gig modules, my PC show the Full 2 gigs. I tested both modules. When I get in the bios it still shows the "PCI MMIO allocation: 4096 MB to 3072 MB" WTF??? It's like it was written in the bios by default...
a b $ Windows 7
December 26, 2010 2:02:15 PM

not to be an ass but, are you certain that your running a 64-bit OS.?

do you have maximum memory selected in 'msconfig'.?
December 26, 2010 2:34:18 PM

yea at this point I think i that is a valid question
December 26, 2010 6:13:36 PM

As i mentioned in the post title and in some replies it is 64 bit. My whole 4 GB used to work before... I tried flashing the BIOS but it is still there, i'm gonna try resseting the CMOS. Any more Ideas?
a b $ Windows 7
December 26, 2010 6:19:57 PM

sounds like you need more sticks of RAM to test out...
meaning I'm thinking that you might have a bad stick of RAM or maybe a bad slot..
pulling the RAM is a good idea but now you need more to test each individual stick..
December 26, 2010 11:23:48 PM

I tested both sticks on 1 slot. they both show 2048mb... Does the ''PCI MMIO allocation'' has to do anything with bad slots?

a b $ Windows 7
December 26, 2010 11:27:13 PM

i think you are over complicating things..
December 27, 2010 6:42:14 AM

I don't know... Ive checked with every solution everyone has said here Ans the problem is still there. I'm not some novice who doesnt knowthe difference between 32 and 64 bit OS. I did the basic Troubleshooting before posting...
a b $ Windows 7
December 27, 2010 10:21:33 AM

did you clear cmos and BIOS.?
is your HDD partitioned.?
December 27, 2010 2:08:07 PM

verbalizer said:
touching the BIOS.?


That's dirty...
a b $ Windows 7
December 27, 2010 3:15:05 PM

LMAO...
January 7, 2011 6:38:14 PM

verbalizer said:
did you clear cmos and BIOS.?
is your HDD partitioned.?

Yep I cleared it and nothing... my HDD has a single partition (C:) 
a b $ Windows 7
January 7, 2011 6:44:11 PM

I have to go back and read from the beginning...
December 14, 2011 5:40:31 PM

verbalizer said:
I have to go back and read from the beginning...

It is true that if you have to use more than 3.25 GiB RAM your BIOS has to support it and you have to use a 64-bit operating system. However, most reasonably recent computers support it and the Windows license 7 key is 32/64-bit agnostic, so you may install the version of your choice with your original OS key.

In general, noobs should never know that there is such a thing as "flashing the BIOS", since the consquences can be dramatical.

About your 4 GB RAM seen as 3072 MB RAM, start msconfig and check "use original startup options".
a b $ Windows 7
December 14, 2011 5:48:23 PM

Quote:
Today I noticed that my system is only using 3072mb of RAM


Define "using" for me: Are you saying Windows can only see ~3GB of RAM, or Windows is only using that much? The first points to a system configuration problem, the second simply points to a lack of understanding how Windows handles memory management.

I see a lot of people suggesting a lot of things without first actually diagnosing the problem...
a b $ Windows 7
December 14, 2011 5:49:41 PM

almodovaris said:
It is true that if you have to use more than 3.25 GB RAM your BIOS has to support it and you have to use a 64-bit operating system. However, most reasonably recent computers support it and the Windows license 7 key is 32/64-bit agnostic, so you may install the version of your choice with your original OS key.

In general, noobs should never know that there is such a thing as "flashing the BIOS", since the consequences can be dramatic.

About your 4 GB RAM seen as 3072 MB RAM, start msconfig and check "use original start-up options".

most BIOS will at least support 4GB of RAM for years now.
maybe a few proprietary system might still limit the capabilities but not retail boards from newegg and such.
so if you have a board that doesn't allow it then odds are it's time to upgrade.
as for the windows license 7 key, I don't know and do not have to worry about that.

and P.S.
I spell checked you post in mine, read mine and then yours.
a b $ Windows 7
December 14, 2011 5:55:26 PM

Quote:
PCI MMIO allocation: 4096 MB to 3072 MB


Based on this, my bess guess is that the IO Addresses of the PCI Bus are being mapped to the upper area of the Address Space, which is the proper Win32 behavior. This should not be happening on Win64, so it looks like the addresses where the PCI bus is being assiged is overlapping the upper half of your memory, cutting down what is avaliable for the OS to use.

A quick google search of the PCI MMIO behavior turns up a LOT of results, I'm reading through them now, and will respond ASAP on a possible fix.
a b $ Windows 7
December 14, 2011 5:58:40 PM

Looks like its a msconfig issue:

http://www.pcmech.com/forum/computer-hardware/215326-wi...

Quote:
Max Memory was set to 3000 MB in msconfig > boot > advanced


Probably need to modify that to read 4GB in your case. I would definatly check what MAXMEM is set to in any case...

Some other related posts:
https://vip.asus.com/forum/view.aspx?id=201011292136000...

http://forums.overclockers.co.uk/showthread.php?p=15346...

Still looking for more posts on the topic, but it seems fairly common...
a b $ Windows 7
December 14, 2011 6:04:15 PM

http://www.vistaforums.com/total-memory-available-only-...

Quote:
This is a BIOS setting . It can be called any of several different things,
but look for a setting to re-map or offset memory in the BIOS and change it
to enable the offset. The issue is that peripheral cards and functionality
need memory addresses and normally these are mapped into the range between
3-4 GB since 32-bit OS's needed the addresses for these cards to be below
the 4GB point. With a 64-bit OS, this 4GB limitation is no longer an issue,
and the memory addresses can be above 4GB, but the BIOS needs to know that
and make the change.


Make sure memory remapping is enabled.

http://www.evga.com/forums/tm.aspx?m=1025804&mpage=1&pr...

Quote:
Ok, here are 3 things. The 1st is a possible BIOS work around. The 2nd is a Windows hidden setting. The 3rd is an explaination of what causes Windows 32 bit to be limited to max of 4 GB, but cannot even use all of that...; some of the first 2 settings (fixes) above help alleviate this problem.
1. In BIOS under Frequency/Voltage / Memory Config set as below:
Memory Low Gap: [Auto]
Memory Remap Feature: [Enabled]
PCI MMIO Allocation: 4GB To 2048 MB
Memory Hole: [Disabled]
DRAM Margin Ranks: [Disabled]

2. In the start/search box or the Run command type " msconfig.exe --- under Tab Boot, click on advanced, then on the right hand side the memory setting is probably incorrect. What I and others have done is uncheck the box (rather than correct the value). Now all memory should be available.

3. Ok, the memory issue detail from Item 1. It is not the x86 chips that have the problem as they are able to address upto 64 GB, but it is the OS / motherboard Architecture of PCIe that causes the issue. You've got memory and devices taking the same memory address space, and the devices win. Remapping the devices moves them way out of the way of the memory, so you don't have the problem. What happens is the MS Windows 7 32bit must use the upper memory space for devices so it cut off memory before 4 GB.
See this link for detail explanation (pay attention to the last section on windows). http://en.wikipedia.org/wiki/3_GB_barrier


The consensus seems to be to enable memory remapping in the BIOS, and uncheck the MAXMEM field in msconfig -> boot.ini -> Advanced.
a b $ Windows 7
December 14, 2011 6:19:29 PM

good work gamerk316..
a b $ Windows 7
December 14, 2011 6:28:26 PM

^^ Basically, without memory remapping, the PCI IO Addresses are overlapping the upper 1GB or so of memory addresses, making them invisible to the OS. Memory Remapping (should) assign those overlapping memory addresses to new unique addresses, making them visible to the OS.

Only other thing that could be a factor is the MAXMEM field, which should be unchecked [NOT ZERO!], allowing the OS to use however much RAM is installed.


One of these days, after hell freezes over and I finish my audio guide, I'm going to write a guide on how windows memory management works under the hood...
a b $ Windows 7
December 15, 2011 11:25:58 AM

For those who want more info:

http://en.wikipedia.org/wiki/3_GB_barrier

Quote:
Modern personal computers are built around a set of standards that depend on, among other things, the characteristics of the original PCI bus. The original PCI bus supported 32-bit physical addresses and 32-bit wide data transfers. PCI (and PCI Express, and AGP) devices present at least some, if not all, of their host control interfaces via a set of memory-mapped I/O locations (MMIO). The address space in which these MMIO locations appear is the same address space as that used by RAM, and while RAM can exist and be addressable above the 4 GB point, these MMIO locations decoded by I/O devices cannot be. They are limited by PCI bus specifications to addresses of 0xFFFFFFFF (232-1) and below. With 4 GB or more of RAM installed, and with RAM occupying a contiguous range of addresses starting at 0, some of the MMIO locations will overlap with RAM addresses.

The BIOS and chipset are responsible for detecting these address conflicts and disabling access to the RAM at those locations.[9] Due to the way bus address ranges are determined on the PCI bus, this disabling is often at a relatively large granularity, resulting in relatively large amounts of RAM being disabled.[10]


Basically, the PCI bus addresses can NOT be placed above the 4GB address, and thus must be within the 4GB range. As a result, there will be memory conflicts when 4GB of RAM is installed.

Quote:
x86 chipsets that support more than 4 GB of RAM typically also support memory remapping (referred to in some BIOS setup screens as "memory hole remapping"). In this scheme, the BIOS detects the memory address conflict and in effect relocates the interfering RAM so that it may be addressed by the processor at a new physical address that does not conflict with MMIO. On the Intel side, this support once was limited to server chipsets; however, newer desktop chipsets like the Intel 955X and 965 and later support it as well. On the AMD side, the AMD K8 and later processors' built-in memory controller supported it from the beginning.


Memory Remapping detects teh conflict, and move the conflicting RAM addresses above the 4GB limit, removing the conflict and making all the RAM addressable by the OS.
December 15, 2011 11:43:59 AM

I had the same problem due to an optimizer (The PowerBooster) tweaking my startup options.

Let me repeat it: just start msconfig, click as told, click apply and reboot. Problem fixed.

And indeed, memory remapping has to be activated in order to use all 4 GB RAM.
!