4GB memory X64

I installed 4 GB ram in my laptop, it's recognized in the bios but x64 see only 3062MB (as the 32 bit version), what can I do to use the full 4GB?

Tom

 

I think in your case it's a hardware limitation. Intel 945 mobile chipsets can only address 3GB (or whatever).

Even by using a 64-bit OS, it's still going to show 3GB.

 

which pc do u have

 

satellite P100-160....if I unterstood 32bit or 64 (in my lucky case) limits the memory to 3GB, do I have any benefit using x64 considering that all the soft I use are x86?

 

I just looked up your laptop and what do you know..

http://uk.computers.toshiba-europe....broadvision.session.new=Yes&PRODUCT_ID=125201

You would probably be better off running a 32-bit OS. More driver and application support.

 

rusmi,

MS has a good answer on this issue at KB article 929605. Due to memory mapping restrictions in the 4 GB space, your O/S, 32 bit or 64 bit, will usually see less than the full 4GB, typically 3 - 3.5 GB.

Here are the details pasted directly from the article and would also seem to apply to WinXP-64 as well:

For Windows Vista to use all 4 GB of memory on a computer that has 4 GB of memory installed, the computer must meet the following requirements:
• The chipset must support at least 8 GB of address space. Chipsets that have this capability include the following:
• Intel 975X
• Intel P965
• Intel 955X on Socket 775
• Chipsets that support AMD processors that use socket F, socket 940, socket 939, or socket AM2. These chipsets include any AMD socket and CPU combination in which the memory controller resides in the CPU.

• The CPU must support the x64 instruction set. The AMD64 CPU and the Intel EM64T CPU support this instruction set.
• The BIOS must support the memory remapping feature. The memory remapping feature allows for the segment of system memory that was previously overwritten by the Peripheral Component Interconnect (PCI) configuration space to be remapped above the 4 GB address line. This feature must be enabled in the BIOS configuration utility on the computer. View your computer product documentation for instructions that explain how to enable this feature. Many consumer-oriented computers may not support the memory remapping feature. No standard terminology is used in documentation or in BIOS configuration utilities for this feature. Therefore, you may have to read the descriptions of the various BIOS configuration settings that are available to determine whether any of the settings enable the memory remapping feature.
• An x64 (64-bit) version of Windows Vista must be used.
Contact the computer vendor to determine whether your computer meets these requirements.

Note When the physical RAM that is installed on a computer equals the address space that is supported by the chipset, the total system memory that is available to the operating system is always less than the physical RAM that is installed. For example, consider a computer that has an Intel 975X chipset that supports 8 GB of address space. If you install 8 GB of RAM, the system memory that is available to the operating system will be reduced by the PCI configuration requirements. In this scenario, PCI configuration requirements reduce the memory that is available to the operating system by an amount that is between approximately 200 MB and approximately 1 GB. The reduction depends on the configuration.

 

guys I found the solution, I installed the service pack vista sp1 rc v.668 and the laptop see 4GB!

 

Was that service pack for 32 or 64 os ???

I have the same sp1(32 bit) installed on mine and your telling me it recognizes all 4 gig.?

 

I think you're confused. Microsoft wanted to end the confusion with having 4 GB of RAM and it not being "recognized" and all that.

In SP1 for Vista, it will recognize how much RAM you have physically installed, NOT how much is actually being used.

This is true for BOTH 32-bit and 64-bit.

 

So your saying that even though Vista knows it has 4 gig of ram installed it will not use it all?

 

I think that would be a yes. Chipset can only handle 4GB's of adresses and some must be reserved for PCI configuration requirements.

 

I wasn't aware of the lack of support of 4 GB in the 945 Chipset, but yeah..

I'm saying that in Vista SP1 32/64-bit, it will recognize that you have 4 GB installed, but depending on you're setup...it won't use it all. This is obvious in a 32-bit environment.

 

That's lame. I can see why they were tired of getting these "why don't my laptop see 4gb" questions, but this is a poor solution.

 

I installed vista x64 SP, my system see all the memory 4GB , before installing the sp I could see only 3GB. I did quick test stitching 15 images in photoshop CS3 before and after the service pack, here the result: before installing SP 7m 25sec, after installing SP 6m 12sec