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4Gb's ram, showing up as 3.12Gb's in Windows XP??

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  • Memory
  • RAM
  • Motherboards
  • Windows XP
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April 26, 2007 7:11:21 PM

I have 4Gb's of PQI Turbo 667 ram installed. I have an Asus P5LD2 motherboard and running Windows XP. It shows the full 4Gb's in the Bios, but when in windows it only reports 3.12Gb's.

Whats the deal?

More about : 4gb ram showing 12gb windows

April 26, 2007 7:24:09 PM

It's because you are using a 32bit operating system. If you were using XP 64bit or Vista 64bit you would get the full 4Gb. Basically its a problem with XP 32bit and not you computer. And no there isn't a way to fix it to use all 4.
April 26, 2007 7:27:36 PM

just curious but do you have onboard video ?
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a b } Memory
a c 98 V Motherboard
April 26, 2007 7:45:10 PM

Vash, its a "problem" with ALL 32bit operating systems, not just XP. This isn't some crazy issue that MS decided to inflict on everyone. A CPU has two states, on or off. (1 or 0) If you have a 32bit CPU, then your CPU can handle 32 of these on or off states. Bring up your favorite calculator, and do the math. 2^32=~4GB. This is the maximum amount of memory pointers that your CPU (and OS) can handle. There simply isn't any more room in the CPU to address more memory. The reason you don't see all the ram in windows, is that the OS needs some memory address space to talk to things attached to the PCI bus. Windows has always attached the early pointers to the ram, and the pointers at the end of the address space to talk to the PCI bus. The problem is some users are installing 4Gbs of memory, and finding out that not all 4GBs of ram is usuable. They are however using all 4GBs of memory pointers.
April 26, 2007 7:50:58 PM

So windows XP supporting up to 4GB of ram is technically not true ?
April 26, 2007 8:10:01 PM

Check your BIOS - my guess is it will read something like this:
Total: 4096
Appropriated: 896
Available: 3200

What you can do in this case is go to Advanced > Chipset.
Here you will find a setting called something like "Memory Remap <something>" (don't recall the exact phrase). It is most likely disabled.
Enable it, the save settings and re-enter BIOS. Now you should have the total amount available.
At least this was the case for me when I had similar problem on an Asus P5W DH Deluxe board recently...
a b } Memory
a c 98 V Motherboard
April 26, 2007 8:22:08 PM

I would say it has 4Gbs of memory pointers. Some of which are required for things other then ram.
April 26, 2007 10:29:50 PM

Quote:
Vash, its a "problem" with ALL 32bit operating systems, not just XP. ....

Not exactly. For many years, x386 compatible CPUs (and many of their chipsets) have had hardware extensions that allow 36 bits of memory address space (Intel calls this PAE), given appropriate OS support. Thus, various Microsoft 32-bit OSs such as most Windows Server OSs can access more than 4GB of RAM. However, if the MB or any add-in cards or any drivers are not designed for these extensions, they will likely cause compatibility/stability problems. 32-bit Win XP originally allowed use of these extensions to address more than 4GB, but analysis of Windows "crash" data showed that MBs/cards/drivers not designed to work properly with addresses longer than 32 bits were causing system "crashes". Thus, Microsoft disabled use of the extensions for 32-bit "consumer" Win XP and 32-bit Vista, allowing only the "natural" 32-bit address size on these OSs.

At least some 32-bit Linuxes have been reported to recognize 4GB of RAM

sam's memory remapping in BIOS presumably works by moving the hardware's memory space above 4GB, leaving all of the lowest 4GB for RAM. Since this results in the various hardware addresses being above 4GB, it's very likely to cause system stability problems in 32-bit Win XP or 32-bit Vista, due to hardware/drivers not properly supporting addresses above the 4GB mark.
a b } Memory
a c 98 V Motherboard
April 26, 2007 10:55:05 PM

If you want to use more then 4GBs of ram, then use a 64bit OS. I don't see the point of trying to "trick" the computer into using all of it.

Frankly, I don't see why 4GBs is needed yet. 2GBs on XP is plenty, and 2GBs on Vista is fine. We aren't at a point yet where home users are needing 4+GBs. So you have 3.12GBs installed, have you even checked what your usage is yet? Are you even using 3GBs? Why try to get 4GBs setup if you don't even go over 3? You can tell me your buying for the future, but I can assure you that in the future there will be something faster AND cheaper.
April 26, 2007 11:30:08 PM

Quote:
Why try to get 4GBs setup if you don't even go over 3?


Because your an idiot and you've already paid for it.
April 26, 2007 11:33:04 PM

Quote:
If you want to use more then 4GBs of ram, then use a 64bit OS. I don't see the point of trying to "trick" the computer into using all of it.

Frankly, I don't see why 4GBs is needed yet. 2GBs on XP is plenty, and 2GBs on Vista is fine. We aren't at a point yet where home users are needing 4+GBs. So you have 3.12GBs installed, have you even checked what your usage is yet? Are you even using 3GBs? Why try to get 4GBs setup if you don't even go over 3? You can tell me your buying for the future, but I can assure you that in the future there will be something faster AND cheaper.


I run Vista Ultimate with 2GB's of RAM, and I'm upgrading to 4GB.

My fully-loaded Vista runs at about 800MB bone-dry. any game that starts using more than 800MB of memory (and there are a lot), and my PC starts swapping to disk.

If you have a bad stick of RAM (i.e. the RAM test fails 3/4 of the way through), then you'll only have that amount available. XP SP2 should provide you with 4 GB if you look in system properties, although no more than 2GB can be allocated to a single process.

Disable fast boot in your BIOS; this will force your BIOS to test your RAM on every hard boot. If you're using Vista, run the memory tester (F8 before the loading screen).
a b } Memory
a c 98 V Motherboard
April 26, 2007 11:36:19 PM

Quote:
Why try to get 4GBs setup if you don't even go over 3?


Because your an idiot and you've already paid for it.

Well sure, there is that reason....

Some people might need more then three, but I'm sure they are the minority.
April 26, 2007 11:36:50 PM

The alternatives are to either switch to 64 bit windows (not recommended) or 64 bit OpenSuse (recommended) or sell the extra gig o ram on Ebay for 60$
April 26, 2007 11:50:18 PM

Quote:
The alternatives are to either switch to 64 bit windows (not recommended) or 64 bit OpenSuse (recommended) or sell the extra gig o ram on Ebay for 60$


*edit*

Even better. Sell your computer and buy a calculator. :roll:
April 27, 2007 12:21:08 AM

Quote:
If you want to use more then 4GBs of ram, then use a 64bit OS. I don't see the point of trying to "trick" the computer into using all of it.

I agree 100%. Using these various paging scheme extensions just makes the system prone to stability problems.

By the time Vista SP1 comes out, more people will be in a position to make some use of 4GB -- I expect that'll be the time of the big move to 64 bit Vista, especially as drivers should be stable and available by then.
April 27, 2007 12:28:24 AM

Quote:
...
If you have a bad stick of RAM (i.e. the RAM test fails 3/4 of the way through), then you'll only have that amount available. XP SP2 should provide you with 4 GB if you look in system properties, although no more than 2GB can be allocated to a single process.....

Not sure if you're suggesting that the issue here is bad RAM; the OP's issue is that because of the 4GB limit on memory addresses under 32-bit XP SP2, and because some of that is used for various hardware, the addressable RAM under Win XP SP2 (and 32 bit Vista) ends up having a practical limit of 3-3.5GB, depending on your hardware.
Here's one discussion of the issues: http://blogs.msdn.com/dcook/archive/2007/03/25/who-ate-...
April 29, 2007 5:36:35 AM

Quote:
It's because you are using a 32bit operating system. If you were using XP 64bit or Vista 64bit you would get the full 4Gb. Basically its a problem with XP 32bit and not you computer. And no there isn't a way to fix it to use all 4.


Actually, you're incorrect. I actually have Win XP x64. If I right click on 'My Computer' is shows that I have 3.75GB of RAM. If I run dxdiag from my run prompt, my DirectX Diagnostic Tool shows 3840MB RAM. It has nothing to do with what OS you are running (x32 vs. x64).
April 29, 2007 12:08:28 PM

Quote:
Actually, you're incorrect. I actually have Win XP x64. If I right click on 'My Computer' is shows that I have 3.75GB of RAM. If I run dxdiag from my run prompt, my DirectX Diagnostic Tool shows 3840MB RAM. It has nothing to do with what OS you are running (x32 vs. x64).


That is because right now, everything wants to be below the 4GB address boundary. And there is not enough room there.

Check your BIOS for a memory remapping feature. This will remap some of the memory above 4GB, so it will be addressable.

Edit: if this is actually your problem. If your graphics card uses shared memory, it will use some of your RAM
April 30, 2007 5:51:15 AM

Actually, it's not a problem for me... I didn't post the original post. Just making a comment. Hell, if you're really that worried about why ALL 4 of your Gig's aren't showing... you might be an addict. :wink:
March 6, 2009 9:14:39 PM

Hmmm...I worry every day that my missing RAM won't come home, just like Little Bo Peep. I must be an addict...
June 29, 2009 12:52:07 PM

I know this thread is old, but hell, it's funny to see people saying that you don't need more than 4 gigs. Heh. I am currently running Vista x64 with 8gigs (beautiful, except for the whole windows thing) and I really wish I had MORE ram. Yup. MORE than 8Gb of RAM. i.e. Photoshop CS4, Logic Pro (for mac. Don't ask me to set it up on your PC unless you're seriously wealthy ;)  ) So..... I'm done beating the dead horse. *passes bat to next in line*
July 17, 2009 3:12:50 PM

HenrikG said:
Quote:
It's because you are using a 32bit operating system. If you were using XP 64bit or Vista 64bit you would get the full 4Gb. Basically its a problem with XP 32bit and not you computer. And no there isn't a way to fix it to use all 4.


Actually, you're incorrect. I actually have Win XP x64. If I right click on 'My Computer' is shows that I have 3.75GB of RAM. If I run dxdiag from my run prompt, my DirectX Diagnostic Tool shows 3840MB RAM. It has nothing to do with what OS you are running (x32 vs. x64).



Well acutally, if you have a system that is set to share memory with your onboard video controllers, if you have any, that's probably why your only seeing about 3.75GB. Your onboard video shares about 224-256MB of RAM based on default settings. If your using a video card, or a graphics card, you should be able to utilize all 4GB on any X64 bit OS, because video card provide their own RAM..

a b V Motherboard
July 17, 2009 5:35:04 PM

IF you expect to see ALL 4 GB of RAM available for apps, you are bound to be disappointed. Sure, some of the address space normally is reserved for access to RAM on the video card, which means that the real mobo RAM in this same address range is NOT being used at all. If you can somehow make the CPU and RAM controllers separately address these two areas, you can get access to the mobo's RAM for use by apps. But besides that reserved address range, there are areas of real mobo RAM that the OS uses for itself. Some of it at the very beginning of RAM is reserved for key pointers. Some is used as buffers for I/O devices. Some are used as addresses remapped to ports on PCI cards. Some space, usually not at the beginning of RAM, actually contains certain RAM-resident portions of the OS itself, including kernel code and drivers. All of this is in mobo RAM and there is NO other RAM in which it can be placed, so that part of RAM cannot be used for applications. Thus we get numbers like 3.75 GB RAM free, even if there is no reserved space for video card addresses. Even a 64-bit OS capable of using RAM above 4 GB cannot avoid reserving some of the real RAM for those purposes.

I can recall the old days of 8086 processors that could access only 1 MB of RAM. Even if you had that much RAM installed, the free space was more like 640 to 750 KB because of all those same factors - RAM actually used by the OS and reserved, plus video card addressing. Even with later hardware like 486 processors and OS's with wider addressing buses, often in a DOS window you still were able to run true DOS applications only within the first 1024 KB, minus the OS reserved space. There were tools and techniques I remember using to optimize the loading and placement of OS components and optional drivers to move as much as possible above the 1024 KB line, leaving less space reserved for DOS in the lower area (and hence more for the DOS apps). So, where did all my RAM go? Been there, done that!
a b V Motherboard
July 18, 2009 3:16:24 AM

4745454b said:
I would say it has 4Gbs of memory pointers. Some of which are required for things other then ram.


-Yeah, 32bit xp/vist support full 4GB however, some of the memory needs to be used by other funamental computer functions thats why you see a bit less of then normal, it support the full 4gb but needs some of it to use for other things besides letting the user to use it :)  64bit operating system can support an exponentially more amount of ram then 32bit. see for 32bit OS, which ever operating system you use will always be 4GB max, however in 64bit, you start getting variations: For example vista home 64 support 8GB, premium is 16GB, and busniss,ultimate,and enterprise support 128GB of ram, some busniss OS like Unix, Sun Solarus and others can support up to 192GB and possibly up to 200GB :)  thats why 64BIT depends more specifically on your operating system.
July 18, 2009 10:09:38 PM

I dont understand why toms video benchmarks, according to the test specifications, use 3 x 2GBs ddr3 ram with a 32bit OS. Why use 6 gbs or ram if the OS only uses 3gb...
a b V Motherboard
July 19, 2009 3:17:41 PM

they dont, they use a 64bit OS.
September 12, 2012 3:20:45 AM

yes i have the same MB p5ld2 but i have 8 gigs of ram installed with a 32 bit os but it finds 5 gigs of the ram and thare is and neerly 2 gigs of ram is use 4 windows and outher stuff to help make it run i have over 3 gigs of ram that i can use i am going to get and install 64 bit os im runing 32 bit vista home p i have a plen d dual core prosseser 3.6ghz oc to 4ghz so its windows and outher programs installed to windows that use your ram i recenly just up graded the video card a nivida g force 8800 with half of a gig of ram and it runs beautifuly once i upgrade to 64 bit os ill update my post and tell you more and see what happens with the ram
!