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Only 2 GB available?


pekka37

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Hello

i hope i have come to the right place for this

 

not so long ago i bought me a Asus P6T deluxe v2 3gb kit corsair DDR3 1600mhz memory and a i7 920 cpu

 

what has been bugging me is that i can onhly use 2040 of these 3gb it only shows 2gb inb windows and bios cpu-z shows trichannel and 3072mb memory that is the only thing that shows my 3gb.

 

so i first thougt a mem slot was gone but then cpu-z couldn´t show 3072 so there has to be some other issue.

 

think any of you can help me?

 

best regards

pekka

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Thread split from X-58 Memory thread.

 

What version of Windows are you using? If you are using a 32bit OS, you will not be able to fully utilize all of your system memory. Please read the article at the link below for more info. The section on Operating Systems is applicable to your issue. Your GPUs each have 1GB of video memory and, your PCI slot addressing takes up a large block of address space also:

 

Memory Upgrade Resource Guide

 

From the article:

 

Operating System

 

Currently there are several considerations for memory upgrades that relate to the operating system. The most common is the use of a 32bit operating system versus a 64 bit operating system

 

Memory usage in 32-bit operating systems

 

Since each binary bit in a 32-bit operating system can be used to represent the location of a byte of memory, a 32-bit operating system has a maximum „memory address size‟ of 232

AN806: Memory Upgrade Resource Guide Page 3

bytes, which equates to 4GB. However, part of this 4GB „address space‟ must be reserved for devices that require MMIO (Memory-Mapped Input Output). As an example, one such device is the graphics card, which requires an amount of address space equal to its frame buffer size (the amount of memory installed on the card) to be „reserved‟ for such data exchanges. This reserved address space is therefore not available to Windows as accessible memory.

 

Memory usage in 64-bit operating systems

 

With 64-bits available to represent the locations of bytes of memory the maximum theoretical memory address size increases to 264 bytes, which equates to 16,384GB (yes, gigabytes!). In reality the 64-bit versions of Windows Vista support up to 128GB, or even more. Therefore, for 64-bit systems, the address ranges for devices that require Memory Mapped Input Output can be set well above the 4GB address line. In summary, a 64-bit system with a 64-bit version of Windows Vista or XP will be able to utilise the full 4GB of installed memory. Users with a 32-bit operating system will also see a significant increase in useable memory of up to 75%.

 

So, what does all this mean to a person purchasing memory? In short, with a 32 bit OS, a system cannot fully address all of the installed system memory. On current motherboards, the PCI architecture will need about 512MB of address space reserved in the MMIO “office block” outlined above. Also, other devices with onboard memory can reserve space in addition to the 512MB PCI block. Video cards, sounds cards with onboard memory, tuner cards, et al can reserve additional space in this upper register area.

 

Real Life Example

Let‟s take the computer I use daily as an example. I built it using the following set of components:

 Asus P5K Deluxe motherboard

 Windows XP 32bit, Service Pack 2

 2 x 2GB of Corsair PC6400C5 DHX

 Abit X600 Pro with 256MB of Onboard Video Memory

If you look at system properties, you can see that I can use 3.25GB of the 4GB of system memory. This is because of the MMIO reservation of 512MB of address space for the PCI devices and the 256MB reservation

AN806: Memory Upgrade Resource Guide Page 4

for the video memory. As another example, if we were to add a sound card with 64mb of onboard memory, the addressable amount of system memory would drop to approximately 3.186MB.

In the configuration above, I have approximately 768MB of system memory that cannot be addressed by the OS. Therefore, it cannot be utilized. However, the positive is that I do have 3.25GB of usable system memory. This is a substantial increase over 2GB so a person should not consider this address space limitation as a reason not to upgrade to 4GB of system memory. Also, 4GB is good advantage at a later date should the user upgrade to a 64bit OS.

For users wanting to fully utilize 4GB or more of system memory, a 64bit OS is required.

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hello i have almost the same kit of ram exept mine is 3GB

so i can´t get the third ram to show up in bios nor windows but cpu-z shows all?

how is that

also i have updated to latest bios, i have tried XMP but still only 2gb

 

so can it be a faulty mem slot although CPU-Z shows all 3gb?

 

i´m going ballistic on this thing soon :

 

regards

Pekka

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hello i have almost the same kit of ram exept mine is 3GB

so i can´t get the third ram to show up in bios nor windows but cpu-z shows all?

how is that

also i have updated to latest bios, i have tried XMP but still only 2gb

 

so can it be a faulty mem slot although CPU-Z shows all 3gb?

 

i´m going ballistic on this thing soon :

 

regards

Pekka

 

POSTS MERGED

 

Please keep your posts in a single thread and do not put your posts on this topic at the end of other threads. It is difficult to assist you when your posts are intermingled.

 

Can you please answer the questions above from your first thread?

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i have a 64bit vista os and i have the memory sticks in the orange slots but only 2gb will be usable i don´t know what to do.

if cpu-z recognizes the 3gb then the motherboard can´t faulty or can it?

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i have the stock cooler from intel you think my mem problem is cpu related?

 

i will check some more but it is wierd it won´t recognize the 3gb i have

 

is it neccesary to reset cmos after a bios update on Asus motherboards?

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Yes, ALWAYS reset the CMOS after a BIOS flash.

 

Some aftermarket coolers will place too much strain around the CPU socket. This causes warping of the board which in turn causes the CPU to not seat correctly. However, your stock CPU cooler should not have this issue.

 

The problem can be 1 of 3 things:

 

Bad CPU memory controller

Bad MOBO memory slot

Bad memory module

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ok i belive the cmos reset is pretty easy on the P6T deluxe v2 motherboard as there is a button or so on the back of the pc if i remember it correctly

when i use sissandra it shows 2gb but 3 modules how is that possible if say one slot is faulty?

i didn´t find any cmos in the manual where can it be?

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  • Corsair Employees
Go to BIOS setup and load setup defaults under the Exit Menu, (Section 4 of the manual) then set the memory Voltage to 1.65 Volts and set the XMP to Profile one and set the QPI Voltage to 1.6 Volts and exit the BIOS saving changes and boot to a disk from http://www.memtest.org and see if it is all showing and will pass two passes.
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ok here goes

i did as you suggested but when mem test ran it ran 2039mb not 3000+

and i took the battery and put it back loaded defaults and when to ai tweaker and chose XMP but iget 1.66 and warning about the cpu may get damgaed permanently so i put it on 1.64QPI i belive the other on 1.35000 i put on 60000 is that correct?

also one of the slots on the motherboard isn´t showing anything but a blue light and if i put one mem module there nothing on screen.

And the other orange slots give me 1016-2040 depending on if i use one module or two.

 

so is it the motherboard or is it the CPU if so how can i find out wich it is?

 

Since i don´t have any other X58 motherboard and a I7 cpu

i forgot Sissandra shows 2gb but three modules...wierd

 

 

 

 

here is a image to illustrate the problem or what it is

 

 

 

 

 

http://img140.imageshack.us/img140/2509/wierdmemoryproblem.jpg

 

 

 

 

 

now how is that possible if a slot is defekt or a bad memory controller-->cpu

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if i choose X.M.P and profile one is all that shows i get 2 values

1.35000v and 1.66(red and warns about CPU damage) is that ok or is it actually harmful for the cpu?

also what does this BSOD mean System service something i can´t read it all as it reboots rather quickly

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excuse me if i am bothersome

but how do i set them up to see if they do work as they should?

also shall i take screenshots so you see if i have done as i should?

 

best regards

 

also i wonder how much is recommended for a I7 system

 

containing cpu 920

motherboard

hd4890

3 1TB HDD´s

and some usb devices like printer keyboard mouse etc.

 

is 3gb too little for this kind of system i also have vista ultimate x64

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hello Ram guy

 

i did as you said default and XMP profile one and i ran the memtest program but still only 2039m of memory is tested it says triple channel but shows only 2039?

so i do guess i have to replace my motherboard that isn´t even 3months old i am so dissapointed in Asus P6T deluxe v2 no other motherboard has given me this much grieve i have had asus for s775 gigabyte s775 this is my first X58 system and it is defect from the start.

 

i so want to go back to s775 but replacing the motherboard should do the trick

 

what i don´t understand is how some apps can show 3gb and some 2gb but shows up 3modules and memtest says triple channel when only 2039 is tested??

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