Why doesn't Windows show all 4gigabytes of memory I have installed?

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Thanks Leo,

This has been driving me nuts for the past 8 months.

Now I find that when I run the GRC utility that Hardware Virtualization is "Locked On"

When I click on that, it tells me:

"This processor's advanced hardware support for virtualization has been enabled and "locked on" to prevent virtual machine penetration compromise. This was probably done by your system's BIOS or by whatever desktop virtual machine system you are using, if any. But if neither are the case you may wish to determine what has done this since it could be a sign of an advanced root kit compromise"

ARRGGH! Now something else to worry about.

try reading your motherboards manual. some motherboards (like mine) asus p5s-mxse, would accept up to 4gig of memory but will show only 3gig(yes! this is much worst!).

If your Vista shows 3326 MB RAM, then everything's fine -- all 4 GB are recognized by the system, but as Leo explained, only 3326 MB are available to the OS.

Now, in the (upcoming) SP1 this information is changed and if you have 4GB of RAM than Vista will show 4GB of RAM regardless of how much of it is available to the OS. I think this "old fashioned" representation of physical RAM makes people more comfy. I just tested the SP1 Release Candidate that's available to public, and indeed the system reports the actual amount of physical RAM -- instead of 3326 MB, it says 4 GB.

Very nice explanation by Leo for something I couldn't understand. He'll get a Latte for this.

Mines worse!!!!

I have a Gigabyte MA-790FX-DQ6 motherboard with a Phenom CPU. I have 8GB of A-Data (2GB each). My board will accept up to 16GB.

At boot up it shows all 8GB, but when I get into WinXP all the shows is 4GB.

Any help here?

So I'm still a bit hazy on something: Is that last bit of RAM still being used somehow (but just now showing up?) or is it "wasted?"

Yes it is being used, for example, if you have a video card with 512MB of memory and 4GB of RAM, a 32bit operating system can only address 4GB when technically you have 4.5GB when you include the memory from the video card.

wow this is a big big help thanks a lot everybody and Leo.. I went CRAZY been going back and forth to the computer store to return the stuff .. the first ram was truly defective because my computer wouldn't start at all..so i went to exchanged it, got a new Ram and installed it just to find out the computer not using it fully "3326" then i wasted the next 30 minutes just to switch the ram randomly ..once again thanks everybody now i can finally feel like i actually bought my Ram.

guyz i am facing a weired prob.

i just installed 4 gb ddr2 ram in my gigabyte ga-945gcmx s2 mobo with intel core 2 duo. but my bios shows 3.25 gb ram ( 340.... bytes). and obviously win xp shows 3.25 gb ram.

then i installed win xp 64 bit pro and it shud show 4 gb ram as its 64 bit os but it also shows 3.25 gb of ram. then i thought ok as bios finds 3.25 gb ram then my mobo must be faulty.

then i logged in my mac leopard os ( i am trying it in my pc as i will be buying a mac air in few days). mac leopard is a 64 bit os. surprisingly mac leopard shows full 4 GB of ram!!!!!!!!!!!!

then i tried everest and cpuz (3rd party softwares which shows system specs). all of these softwares shows 4 Gb of ram.

so though bios is showing 3.25 of ram actually the mobo gets the 4 gb ram. but i still cant find why win xp 64 bit cant find the 4 gb ram.

Hi, i have simular prob's. i installed 4 gb of dual ddr2 mem into my pc and only 3 gb show up in properties under right click comp. you said previously that was worse..?? what could be wrong or please explain why it is worse. thanks

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