Missing a Gig of Memory

Question

Hi all:   I recently purchased a computer that was suppose to have 4 gigs or ram.  But when I start it up, it says that there are only three.  But if I hit F2 when it is starting up, it sees that there are in fact 4 gigs availible.   So why when it is running, I lose a whole gig worth of memory?  Where does it go?   Thanks for your replies.

pcgeek11 · Answer

Check This thread. http://www.dellcommunity.com/supportforums/board/message?board.id=vista&message.id=9737#M9737   Most answers are here if you search first.   pcgeek11

ltop · Answer

You must be running XP - that's normal (for XP).  Vista will address all that RAM.

gdwrnch3 · Answer

A windows x86, or 32 bit OS will only 'see' 3 gigs of ram.

borisb · Answer

I have Vista Ultimate 32-bit on my M1710, and it only  sees 3.25 Gb of the 4 Gb installed.  Apparently it's a BIOS/system thing, not the OS.

Stikboy · Answer

Check your BIOS and see if the memory is allocated to your video card. If you have onboard video and it's using shared RAM then it would likely only show you 3.25G of the 4. If you have an add-on card for video, it might not have properly shut off the onboard card. I had the same issue with a Dimension 521.

brokenpen · Answer

Does anyone know if it will be 'fixed' in the near future.  It is pointless to have installed 4 gigs and pay extra to have those 4 gigs if it is not useable.

brokenpen · Answer

How do I check to see if the video card is using some of the memory?  If the video card is stealing some of it, I certainly will not complain as the memory is in fact being used.    What my computer says is that there is 3070MB of RAM availible.  I did see somewhere that the video card had 568MB (my card is only 256) but for the life of me, I cannot remember where I saw that.  And if this is true that the vid is taking some of it, then where is the rest going?

Stikboy · Answer

Sounds like the onboard card is using the memory. In the BIOS look for the hardware/on-board devices and select the video card. The right side of the screen will show you options for Off, 128M 256M 512m 1G. If you have an add-on card, choose off - and make sure you monitor is plugged into the add-on card (I know, it's a given, but you'd be suprised how many people order a Dell with an add on card and still attach the monitor to the onboard during setup...)

pcgeek11 · Answer

If you checked the link above, you would have seen:

Posted earlier but here it is again:

The 32-bit versions are artificially limited to 4G meaning that they will never touch an address greater than 4GB no matter how much memory is installed even if PAE is enabled.

The reason you only see somewhere between 2G and 3.8G is because the hardware requires some of those memory addresses to work. And it also seems that PCI-E video cards get their entire memory range mapped into the host's memory so if you have a card with 512M of memory you'll lose 512M worth of physical memory addresses.

If you enable the memory hole in the BIOS it'll remap the physical memory above the 4G mark so that it can be used again, but you'll need an OS that actually let you use those addresses and 32-bit XP and Vista aren't in that list.

You would need Vista X64 bit or one of the other OS choices Linux X64 ... to be able to actually see the address' above the 4 Gig Limit in the 32 bit versions.

pcgeek11

scottwilkins · Answer

PCGeek11, sorry but you are incorrect on diagnosing this problem. I have an M1710 with 4 Gig memory that I just upgraded from 2 Gig. It appears that the BIOS, of which I installed the latest, is not working properly. I'm running the 64-bit version of XP Pro, so I should see all 4 gig, but I'm not. Upon booting into the BIOS, there I can see that the system does in fact see 4 Gig memory, but the BIOS screen where memory is shown is stating on my system that only 3.3 gig is available. I have a descreet nVidia 7950GTX card in my M1710, so there is no memory sharing for the video.

I've seen this in desktop boards. Upgrading the BIOS on those boards moved them from 3.3 gig to a full 4 gig. Of which all 4 was properly reported and used in both 64 and 32 bit versions of Vista. Though XP Pro still only reported about 3.3 gig available, due to the problem you state.

Since this is apparently a BIOS issue, then the OS problem you state should be affect the correct amount being reported in a properly setup and working OS that should see all 4 gig. Besides, in the BIOS for the M1710 I cannot find a way to toggle the memory hole, like I've seen many times in other BIOSes. Not sure why it's missing in the M1710 BIOS.

Message Edited by scottwilkins on 05-03-2007 09:56 PM

scottwilkins · Answer

Again, I state you are in fact wrong with the Dell laptops.  It is not possible to re-map the memory hole, and the BIOS is not allowing full access to the 4 gig memory.  If you'd like to state a way to actually do the re-map then I'll retract my statement.  Until then, you are mistaken on the method for fixing the problem.  From looking at your Sig, it seems you don't have a model for which you can even test your theory.

pcgeek11 · Answer

scottwilkins,   No I am not wrong. Do some homework and you will see that I am in fact correct. I didn't say that the video card would be the only system device that would consume RAM but it is one of the bigger possibilities. Lots of system devices use RAM.   pcgeek11

scottwilkins · Answer

In re-reading your statements, I'm finding that you have even more errors in your logic.   The 'system devices' do not use the ram that is missing.  They mask it.  In order for the system and OS to access any device on a system it has to be able to address it.  For those who have been in the IT biz as long as I have, they also know that was one of the original reasons behind the old DOS 640K limit as the BIOS, video and other devices actually reside in the 640 to 1 meg memory address space.  Even today, they still reside there, but the BIOS is able to swap that memory with the hardware mapping, giving it all to the OS.  Memory mapping has come a long way since then, and most BIOSes allow the 'add-on' devices to be mapped in virtually any space within a 4 tetrabyte addressing allowed by a modern processors, and available since 64-bit extentions have been added to both AMD and Intel processors.  After all, they both do have 128-bit memory channels.  That is if the BIOS is up-to-date with modern processor abilities.  My examination of the problem gives me reason to believe Dell has not properly programmed the Inspiron and XPS laptop BIOS chips to allow this addressing ability.   I find the extremely odd since they do currently sell the laptops with up-to 4 gigs memory from their factory.  I wonder how they explain that to their customers using 64 bit OSes?  I have not yet found any explanation in their support FAQs or other resources, not that their easy to search, they are not.  I will probably call Dell's XPS support on this in the near future.  If they are able to provide any insight beyond the 'well your OS can't see this' bull hockey, I'll be sure to let you and others know.

pcgeek11 · Answer

scottwilkins,

Again you didn't read my post completely: Let me explain it:

I said:

Point # 01.

The 32-bit versions are artificially limited to 4G meaning that they will never touch an address greater than 4GB no matter how much memory is installed even if PAE is enabled.

^^^ Greater than 4 GB you cannot use with 32 bit Windows PERIOD. ^^^

Point # 02.

The reason you only see somewhere between 2G and 3.8G is because the hardware requires some of those memory addresses to work. And it also seems that PCI-E video cards get their entire memory range mapped into the host's memory so if you have a card with 512M of memory you'll lose 512M worth of physical memory addresses.

^^^ I am talking about address spaces NOT Actual Memory here. ^^^

Point # 03.

If you enable the memory hole in the BIOS it'll remap the physical memory above the 4G mark so that it can be used again, but you'll need an OS that actually let you use those addresses and 32-bit XP and Vista aren't in that list.

^^^ I didn't say that this was applicable to Dell Notebooks, but this is a way on a computer with a Unrestricted BIOS that allows these types of changes, and using an OS that can actually use memory OVER 4GB. This is in the Software Forum and not specifically for Portables... K

Point # 04.

You would need Vista X64 bit or one of the other OS choices Linux X64 ... to be able to actually see the address' above the 4 Gig Limit in the 32 bit versions.

This is not a Dell Problem Most computers have this very same issue. As I stated earlier an X32 bit Windows is artificially handicapped to a maximum of 4 GB.

Point out what is wrong exactly and why.

I'm open, but I am still correct in my previous post.

Just because it is not in my sig doesn't mean anything.

pcgeek11

Message Edited by pcgeek11 on 05-04-2007 12:28 AM

pcgeek11 · Answer

Looks like you squeezed a post in while I was composing:

This: " In re-reading your statements, I'm finding that you have even more errors in your logic."

My statements are not based on My Logic, but they are based on facts that you choose to ignore.

This: " The "system devices" do not use the ram that is missing. "

Nobody stated that they did. I stated address space.

This: " For those who have been in the IT biz as long as I have, "

OK. How long is that, so we can be adequately impressed.

This is impossible: " Even today, they still reside there, but the BIOS is able to swap that memory with the hardware mapping, giving it all to the OS."

When you use memory space for X, Y, or Z, that means it is used and this deducts from the total amount of system memory that can be mapped. If a sheet of paper has 10 lines on it to write. If you use two of those lines for anything then that only leaves 8 lines available to use. As long as the memory map has enough space to map all of the system memory, and the (as in a 32bit OS) maximum memory is not exceeded then you will see and use the memory. But as I stated earlier Windows 32bit OS is ham strung by only being able to map 4 GB Total. Regardless of the BIOS Windows will only report 4 GB minus what is mapped for system devices. I think you are getting confused on the differences between what the hardware and firmware support and what is the limits of the operating system X32 bit. You cannot Blend hardware, software, and firmware limits together to try and make an argument to support your " cause ".

This: " most BIOSes allow the "add-on" devices to be mapped in virtually any space within a 4 tetrabyte addressing allowed by a modern processors, and available since 64-bit extentions have been added to both AMD and Intel processors. "

This will not do a fat lot of good if the OS will NOT See or Use anything greater than 4 GB. Example Windows any flavor X32 bit.

Here is what Microsoft Says: and it looks like I was incorrect about the PAE not working in Vista IAW What MS says. I still have doubts about PAE.

***************************** From Microsoft KB *************** Article ID : 929580 Last Review : March 5, 2007 Revision : 2.0

SYMPTOMS

On a computer that has 4 gigabytes (GB) of random access memory (RAM), the System Properties dialog box and the System Information dialog box may report less memory than you expect.

This problem occurs in Windows Vista and in Windows Server 2003.

CAUSE

This problem occurs because the address space is limited to 4 GB in a 32-bit hardware environment. Memory may be relocated to make room for addresses that the basic input/output system (BIOS) reserves for hardware. However, because of this limitation, Windows Server 2003 and Windows Vista cannot access memory that is relocated above the 4 GB boundary.

MORE INFORMATION

A 32-bit operating system can address memory that is relocated above the 4 GB boundary if the following conditions are true:

• The computer is in Physical Address Extension (PAE) mode. • The computer has 4 GB of RAM.

In this case, the operating system correctly reports how much memory is installed.

Additionally, some x64-based operating systems can address up to 2 terabytes (TB) of RAM. For more information, visit the following Microsoft Web page:

http://www.microsoft.com/technet/windowsserver/sp2/overview.mspx ( http://www.microsoft.com/technet/windowsserver/sp2/overview.mspx)

To enable PAE mode, you have to add PAE to the boot entry in the BCD file. Open an elevated command prompt. Type Run BCDEDIT /SET PAE ForceEnable.

Note There is no Boot.ini file in Windows Vista. The Boot.ini file is used for legacy Windows versions when dual-booting only

If you add more memory to the system, the BIOS might recognize all the physical RAM even though Windows recognizes only a part of the RAM. If the computer uses a redundant memory feature or a memory mirroring feature, the full complement of memory may be invisible to Windows. Redundant memory provides the system with a failover memory bank when a memory bank fails. Memory mirroring splits the memory banks into a mirrored set. You can enable or disable these features by using the BIOS. You cannot enable or disable these features by using Windows. To modify the settings for these features, refer to the computer's user manual or to the BIOS manufacturer's Web site. Or, contact the manufacturer.

For example, if the computer has 4 GB of RAM installed, and you add 4 GB of additional RAM, Windows may recognize only 4 or 6 GB of RAM instead of the full 8 GB. The redundant memory feature or the memory mirroring feature may be enabled on the new memory banks without your knowledge. These symptoms resemble the symptoms that occur when you do not add the /PAE switch to the Boot.ini file.

********************************************************

Message Edited by pcgeek11 on 05-04-2007 02:39 AM

Windows General

Missing a Gig of Memory

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