Memory Count is lower than is what's installed.

By len.piko ·
I installed brand 4gb new kingston memory. When I go to system the summary of 3.25GB displays. Can anybody tell me why the count differs from the installed memory?

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by Wizard-09 In reply to Memory Count is lower tha ...

Goto your bios and check the information on there, also your MB might be able to handel 4gd and thats way your receiving only 3.25.

Keep us informed as to your progress if you require further assistance.

If you think that any of the posts that have been made by all TR Members, have solved or contributed to solving the problem, please Mark them as Helpful so that others may benefit from the outcome.

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by unhappyuser In reply to Memory Count is lower tha ...

You may have an incompatible or defective simm. Do you have another machine that you could try it in? Try pulling memory from another machine, which has an accurate memory read, and compare numbers.


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Memory Count is lower than is what's installed.

by len.piko In reply to incompatible

I was told that win xp home edition will only support 3.25gb of memory. They said that I would have to go to a 64bit OS.

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This is true

by The Scummy One In reply to Memory Count is lower tha ...

however, it isnt just XP home edition, it is all 32-bit OS's.

The memory that you do not see is being used by the system for system board components, video RAM (shared or other), and other devices plugged into the MB. What is left is the available memory that us useable.
a 32-bit OS can only access 4GB Ram, and a current motherboard/video can eat up .75 to 1.25GB in order to operate.
As a test to watch -- go get a 1GB video card and plug it in. You will likely lose a large chunk of that RAM listed currently.

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by Snuffy09 In reply to This is true

"go get a 1GB video card and plug it in. You will likely lose a large chunk of that RAM"

Only onboard video consumes your ram. Thats why you buy 256, 512, and 1GB cards right? VCards obviously perform better but they have their own memory also.

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re: Physical RAM and Virtual RAM

by ThumbsUp2 In reply to ?

Even if you put an external video card into the system, the Physical RAM above 3.25GB (more if needed) is reserved for use by the system as Virtual RAM so that it can communicate with the 1GB physical RAM on the card. Thus, the bigger the video card you install, the more Physical RAM located on the motherboard will be reserved for Virtual RAM.

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I dont think

by Snuffy09 In reply to re: Physical RAM and Virt ...

I have ever seen an obvious drop tho. If my OS states my computer has 3.2GB (4gb) installed and i install a graphics card that has a bigger memory cache i am still said to have 3.2.

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It is to do with the way that the OS Addresses the RAM that it has to deal

by OH Smeg Moderator In reply to I dont think

In this case Video RAM is added to System RAM and while they do different things they are still addressed by the same part of the OS which can not exceed it's upper Limit.

As Video RAM is given Precedence over System RAM any Video RAM installed is deducted from the Available System RAM after a certain Point is reached so in the case of a 32 BIT OS the more Video RAM that you have installed the less System RAM will appear.

In the same vein if you use a Video Card with a smaller RAM Load the size of the System RAM will increase though you will not get any better performance and it may even be worse with some applications that are Video Intensive.

Every 32 Bit OS no matter what it is hits the upper Limit around the 3.2 GIG Mark and can not make full use of this extra RAM.

But of the + side if you have Dual Chanel RAM fitting 2 X 2 GIG Ram Sticks or 4 X 1 GIG RAM Sticks will give you the best performance that the unit can achieve with that CPU and M'Board Architecture so while some RAM can not be utilized once you exceed the 32 Bit OS's upper Limit it still allows the M'Board to work in the best possible way or fastest manner possible.

Also if you where to fit 1 X 4 GIG RAM Stick the system would be slower than if it had 2 X 2 GIG RAM Sticks Fitted as the M'Board would switch to Single Chanel Mode.

Naturally if you switch to a 64 Bit OS you will be able to use all of the installed RAM that the M'Board can support and the Biggest Video Card that you can buy. But no matter what you do the Video RAM will always take precedence over System RAM. This is just the way that things work.

Where Video Cards offer improved Performance over Integrated Video is because Video Cards use Faster RAM and have a Better Architecture to optimize the Performance of the components used to make them where as Integrated Video uses the Slower System RAM and it is not optimized as well because of the design limits imposed on the builder of that Circuit Board.


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This is because it does not need more......

by ThumbsUp2 In reply to I dont think

I have found several articles which explains it better than I can. However, the following discussion does the best at explaining it so I could get my simple mind around it. Basically, the space above about 3.2GB is reserved and only used if needed. If you have more than just a video card which needs the space you MIGHT see a decrease in available RAM.

copied from part of http://www.tomshardware.com/forum/244323-30-tomshardware
RetiredChief wrote :

Most of you have already said, and correctly so, that winds Xp and Vista 32 bit can except up to 4 Gis memory. But as you also pointed out you "see" less than.

This is a throw back to the "Old" DOS days where you had 640KB for programs and a reserved 384KB called upper memory.

Memory-Mapped I/O (MMIO), for example (Not limited to) video memory must be mapped within the first 4 Gigs of memory. In systems with less than 4 Gigs of physical memory this MMIO is placed in the virtual memory, But when 4 gigs of physical memory is used, it then must resided in that 4 gigs. (4096 - 384 = 3680 or the 3.6 gigs that is the MAX that is available for programs.

Vista (32 Bit) places a limit on grogram memory at 3.12 Gigs, UNLESS the BIOS support Memory remapping.

Reference http://support.microsoft.com/kb/929605

russki wrote :

Chief, while I ordinarily agree with you, (and your link does not work so I'm speaking from memory of reading through that KB and general concepts), I don't think you are entirely right.

1) You are right that the MMIO and other reasons to reserve the memory address ranges is a holdover from the older times (however, architecturally, it is one of the better ways to handle that and it is really tough to conceive a more viable alternative that makes programming as simple as this method). For the poster that asked to have this explained further, this is how it works in a gist. For certain IO (input / output) operations, an "ease of use" feature was designed that allows the code to just reference a certain memory range, and the system knows that the data written should, in fact, go not in the system memory but to a device. Hence the term memory-mapped-input-output (MMIO). The only problem with that is that the address range that is reserved for this IO should then be unavailable to general programs, because it is now dedicated to the interface with that particular devices (video card, sound card, etc.). This was never really a problem until recently, because...

2) It is a limitation of the x86 architecture and a bit of the Windows design that only a total of 4Gb may be addressed (32bit address space). Until recently this was not an issue at all because system memory of 4 Gb in the desktop space was really unheard of. Now that it's becoming a reality and moving towards the norm, the issue has reared its ugly head.

3) Since you can address a total of 4Gb but some of it has to be reserved for MMIO (and other things similar in concept), that limits the amount of physical memory that is addressable for the purposes of memory access. This is what limits the amount of physical memory shown by the system even though you have more installed. This occurs on the system level.

4) Separate Issue Altogether: Typical application gets a total address space of 4Gb (no matter what amount of physical memory is installed. This is because virtual memory has been a component of the system for a long long long time). To account for the MMIO, etc. needs and other system needs, the "User Space" - that space available for the application to address physical memory, it typically limited to 2Gb (unless the /3Gb switch is used). This occurs on the application level. This presents other problems, again, unrelated to what physical address range in visible to the OS. For more see the Anandtech article quoted above.

5) 64 bit OS allow for a workaround of the first issue. This is where I respectfully disagree with the Chief. You have to have a 64bit OS (not sure if limited to Vista, but let's face it, 64bit XP is worse than Vista). You also need to have the chipset that supports more than 32bit of address space (not all do, even those that support 64-bit processors. Which is ironic). You need the processor that supports 64-bit addressing. And your BIOS needs to support a "memory remapping feature." That feature remaps the address space reserved above the 4Gb line. So then you can actually address all of the 4Gb memory installed (and / or more).

---end of article---

My own list of various articles of interest

The system memory that is reported in the System Information dialog box in Windows Vista is less than you expect if 4 GB of RAM is installed



A description of the 4 GB RAM Tuning feature and the Physical Address Extension parameter



Windows Vista SP1 includes reporting of Installed System Memory (RAM)



RAM, Virtual Memory, Pagefile and all that stuff



Windows Vista SP1 includes reporting of Installed System Memory (RAM)
(system information is displayed differently after installing Vista SP1)


Error message when you try to install Windows Vista on a computer that uses more than 3 GB of RAM: "STOP 0x0000000A"

(another bit of information which is related)



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Address Space Not Actual RAM

by TheChas In reply to ?

It is not that you loose RAM, or the system uses the upper RAM. It is that the address space for the upper RAM is reserved for hardware support and basic house-keeping tasks. Since the address space is being used at the hardware level for other functions, the operating system cannot access any RAM that is in the reserved address space.

And yes, if you install a 1GB video card, most systems will end up with a maximum addressable RAM of around 2.5 GB. How much addressable RAM any system has depends on the specific chip-set, BIOS and hardware installed.

Ever since 32 bit processors have been around, the upper address spaces have been used as temporary pointer and reference locations for the CPU and chip-set to handle the hardware. This did not become an issue until RAM density increased and prices allowed configuring motherboards with 4GB or more RAM. Add to the issue 64 bit capable motherboards with the capacity for 16GB or more RAM running 32 bit operating systems.

Intel published a very detailed white paper on this. But, the last time I went looking for it, I could not find the link.

IMHO, if you install more than 3GB of RAM on a system that has a 32 bit OS, you are simply throwing money out the window. Both the cost of the 4th GB of RAM, and the ongoing cost for the power to run the RAM are wasted.


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