4GB RAM.. OS detects only 3GB?

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TomHax

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Topic # 57314 9-Feb-2010 13:33

Hi GZ Forums!

I am back once again with a smaller, less significant problem this time. I'm really just looking to have a few quick questions answered.

I purchased and installed another stick of 2GB DDR2 RAM today. I now have 4gigs of DDR2 RAM total.

When I right-click 'My Computer' and look under the 'General' tab, I notice it says I have only 3gigs.

Now before you proceed to sigh and whisper "amateur" under your breath, let me tell you I HAVE consulted with Uncle Google, and HAVE received sufficient answers to this seemingly insignificant dilemma.

-HOWEVER-

I appreciate the personable knowledge and expertise of my fellow GeekZoners above all other forums and various informative webpages.

Is this statement true?:

"You have 4GB installed in your system. Windows is "seemingly" only allowing you to use 3 to 3.5GB. This is because Windows is RESERVING 500MB (.5 GB) to 1GB of your 4GB to BOOT from and run NECESSARY BACKGROUND SERVICES as well as your SYSTEM DEVICES (USB,etc). Thus, only 3-3.5GB is accessible by Windows and its applications."

Why does this occur on 32bit Operating Systems? Will my PC recognise and utilise an entire gig of RAM despite it not being listed? Will my PC operate as though it was using 4gigs of RAM even though Windows perversely states it isn’t exactly?

Many thanks,

~TomHax

freitasm

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Reply # 297374 9-Feb-2010 13:44

The whole explanation is here and it's to do with the way 32 bit addresses memory.

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NZCoderGuy

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Reply # 297376 9-Feb-2010 13:47

I concur - i was just about to reply, stating that Windows 32Bit can't access the full 4GB of ram - due to memory addresses issues. Best to upgrade to 64Bit if possible to make the most of it.

--
Stephen
twitter/ NZCoderGuy / KiwiDevStudios

TomHax

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Geek

Reply # 297378 9-Feb-2010 13:55

Thanks freitasm. Excellent article! Answered most, if not all the questions I had.

So in the end.. my system really only utilises 3-3.5gigs of RAM? Correct?

dacraka

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Reply # 297389 9-Feb-2010 14:44

Basically if you boot up your BIOS it will tell you how much RAM your motherboard can see.

Generally if it says 4GB in the BIOS, all you should need to do is upgrade your Operating System to a 64bit version.
If your BIOS reports 3GB, then a firmware upgrade is necessary to make your motherboard see the entire 4GB (not all firmware upgrades will fix this problem however!).

Correct, your system will generally only utilise whatever it says in your "My Computer"/"General" tab.

TomHax

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Geek

Reply # 297441 9-Feb-2010 18:03

dacraka:
Generally if it says 4GB in the BIOS, all you should need to do is upgrade your Operating System to a 64bit version.

My BIOS says 4GB. See for yourself:

Does this mean I have a 64-bit motherbaord? It'd be awesome if I did!! In that case I would absolutely update my OS to a 64-bit version. Also if it meant the RAM would be fully utilised then I think it would be well worthwhile.

What are your opinions? How do I know if I have a 64-bit motherboard?

freitasm

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Reply # 297443 9-Feb-2010 18:10

Download http://www.cpuid.com/cpuz.php... and see what motherboard and CPU you have.

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freitasm

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Reply # 297444 9-Feb-2010 18:11

Better still. Run this small program and it will tell you if you have a 64 bit processor: http://www.grc.com/securable.h...

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TomHax

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Reply # 297465 9-Feb-2010 19:09

Okay, well I ran the "Securable" app and it says I have a 32bit processor. I guess that's that then?

What a pity, I was excited for a moment there..

Also, the DirectX Diagnostic Tool states there is only 3070MB of RAM available. I guess I'll just have to accept the fact the RAM will never quite be used to its full potential. Ah well.