[TheWicked]

The ram shows up in my XP/vista as 2gb, although on CPU-Z it is reflected 3gb and all 3 rams are detected. Why would this be? I also took a look at the max memory setting in msconfig, it does not allow me to set more than 2048 as ram.

The video card is a 9600gt and it has its own onboard ram, so I doubt this is a result of ram being shared by the video card.

Any ideas? thanks.

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[無名]

seems like u using "un-official vista" , its a bug if im not wrong.

[TheWicked]

bug? wah...

cos i noe 32bit by right can support up to 4gb ram ma...

i notice the same thing on my xp as well.. this pc is dual boots to vista and xp.

[TheWicked]

i guess it is time to upgrade to 64bit edition.

[無名]

i suggest dont use those ver that is modify by ppl.. cnfm got lots of bug.

[TheWicked]

found out why already..

posting here to share

In a computer all bytes in the memory system need a unique name. This is called an address. For example, if you have 2 GB of main memory, then there are 2147483648 bytes of RAM in your machine, each of which require an address for the operating system to communicate to it. To give these all an address you need 31 bits to do it. Now, if/when you have 32 bits, you can name 4 GB (2 bytes to the 32nd power = 4GB).

This is why the total addressable space available in a 32 bit OS is 4GB – the OS runs out of addresses and cannot communicate/locate any more bytes of memory because of that.

You may think ”Hey, 4GB of address space… 4GB of RAM… What’s the problem” The problem is that memory isn’t the only thing needing an address. If you install a total of 4GB worth of RAM, the system will detect/use/display less than 4GB of total memory because of address space allocation for other critical functions, such as:

- System BIOS (including motherboard, add-on cards, etc..)
- Motherboards resources
- Memory mapped I/O
- Configuration for AGP/PCI-Ex/PCI
- Other memory allocations for PCI devices

Different onboard devices and different add-on cards (devices) will result of different total memory size. e.g. more PCI cards installed will require more memory resources, resulting of less memory free for other uses.

This limitation applies to most chipsets & Windows XP/Vista 32-bit version operating systems. Again, this is a limitation of the Operating System not having enough address space to allocate to the system *and* the RAM. Not allocating address space to devices renders them inoperable. Not allocating addresses to RAM simply results in the unaddressed section not being used in an otherwise fully functional computer. Therefore the OS designers assign RAM last.

We can have long debates about mathematical fundamentals and discussions about why the original Windows designers couldn't allocate the full theoretical max of 36 bits of address space so that users today would be able to use more resource. But at the end of the day, the designers and engineers 'Didn't Then'. So we 'Can't Now'.


If you install a Windows operating system, and if more than 3GB memory is required for your system, then the below conditions must be met:

1. A memory controller which supports memory swap functionality is used. The latest chipsets like Intel 975X, 955X, Nvidia NF4 SLI Intel Edition, Nvidia NF4 SLI X16, AMD K8 and newer architectures can support the memory swap function.

2. Installation of Windows XP Pro X64 Ed. (64-bit), Windows Vista 64, or other OS which can provide more than 4GB worth of address space.



Note: According to the latest Change Log published by Microsoft, Windows Vista 32bit SP1 will display the installed amount of RAM. This is a display change o

So if i have 3gb ram i suspect i will still have 2gb useable by OS even if it is 64bit, however, processes will be able to use more than 2gb virtual memory (includes physical ram and paging)..

However once i upgrade my ram to beyong 4gb... vista 64bit will be godlike?

Also I read that even though gpu has onboard memory, we will be denied that same amount of memory from system ram due to addressing issues... Quite silly leh...

[TheWicked]

Originally Posted by 無名

i suggest dont use those ver that is modify by ppl.. cnfm got lots of bug.

but some pple prefer these modified versions even if they have the original version because they are supposedly more streamline... however stability is indeed an issue.

[無名]

modify version is indeed lighter, ram usage lower and lots of things be taken off/ tweaked. Stability wise im not too sure as i never use before.

64bit vista Ultimate can support 128GB of ram, 64-bit Home Premium supports up to 16 GB of RAM and 64-bit Home Basic supports up to 8 GB of RAM.

Do u need so much ram?

A Closer Look at Windows Vista, 32-Bit vs. 64-Bit Windows

[TheWicked]

Originally Posted by 無名

modify version is indeed lighter, ram usage lower and lots of things be taken off/ tweaked. Stability wise im not too sure as i never use before.

64bit vista Ultimate can support 128GB of ram, 64-bit Home Premium supports up to 16 GB of RAM and 64-bit Home Basic supports up to 8 GB of RAM.

Do u need so much ram?

A Closer Look at Windows Vista, 32-Bit vs. 64-Bit Windows

no la, but main issue is i just earnt xp and vista 32bit got a 2gb limitation on how much memory each application can address. U can tweak it to 3gb but that comes at an expense of lesser memory allocated for OS workings. Going 64bit would solve this problem. (Perhaps this is why cygig's photoshop keeps lagging due to out of memory even with core i7 and 3gb ram... becos the 32bit photoshop can only use 2gb of virtual memory.

[xdeadx]

could be your gpu, is it those graphic cards that share ram with your system memory ?

[cheesified]

it might be the gpu

[TheWicked]

GPU is a 9600GT with 512mb on board.. however i read that due to addressing limitations, 512 will still be deducted from overall addressable memory which is what i commented to be very weird..

Pull one of your graphics cards and you will see another ~512MB
Pull both and use a crappy 32mb vid card and you will see even more.

Windows XP 32bit can only ADDRESS 4gb total. That includes system ram, gpu ram, registers, blah blah blah. I've read that dual-channel doubles the ram needed to be address by your video cards - but I have not tested this myself. So if you have a 512mb vid card it will use 1gb of address space.

Move to XP 64bit and windows will be able to adderss all 3gb of your ram.

There's also some techdoc from Microsoft that SP2 will address less of your ram then SP1 - it has to do with compatibility of some sort.

Saw it on OCers forum

this is omgwtf.

Alot of pple asking the same thing... see this google search result.

I am using 3 stick of Corsair 1gb ddr3 ram.


but someone else said it is due to asus, not coincidentally, i am using Asus P6T SE. Could that be a problem?

Hmm where does this notion come from? It's true that XP has memory allocated to PCI adaptors and RAM can be allocated to the video cards but I've never seen the case where pulling the card would allow XP to read all the memory. Actually XP is only able to access 2gbs in it's vanilla form and with SP2 it was able to access 4gigs using PAE. I've used XP with 3gigs and 2 video cards before on a DFI board and it was fine but Asus has always given trouble because of their BIOS.

Thing is i google liao everyone give different explaination that seems right.. but i donno which is the really right one.

Does size of paging file also play a part? I will try changing to 1gb paging file and see if all 3gb ram is accessible. I think my vista defaults paging file memory at 2gb

From microsoft KB

has 256 MB of onboard memory, that memory must be mapped within the first 4 GB of address space. If 4 GB of system memory is already installed, part of that address space must be reserved by the graphics memory mapping. Graphics memory mapping overwrites a part of the system memory. These conditions reduce the total amount of system memory that is available to the operating system.

The reduction in available system memory depends on the devices that are installed in the computer. However, to avoid potential driver compatibility issues, the 32-bit versions of Windows Vista limit the total available memory to 3.12 GB. See the "More information" section for information about potential driver compatibility issues.

If a computer has many installed devices, the available memory may be reduced to 3 GB or less. However, the maximum memory available in 32-bit versions of Windows Vista is typically 3.12 GB.

[TheWicked]

knn problem solved.

Turns out one of the RAM is disdodged (donno why also).

Still weird that CPU-Z is able to detect the 3 sticks of RAM, when windows can only detect 2.

[無名]

glad it solved

[TheWicked]

yepp... caused me lots of frustration finding the cause, only for it to be so simple.... %^*(_)