Slightly different memory question

Jason Crain jason at
Wed Jan 7 15:29:18 UTC 2009

On Wed, January 7, 2009 9:09 am, Mark Haney wrote:
> Scott wrote:
>> 	I have a Inspiron 1525 with 4GB of Ram and I noticed through system
>> monitor that the 32-bit Ubuntu sees 3.5GB of that.  I know my video card
>> uses 256MB, so does this mean that I am using a total of 3.75GB or is
>> that 256MB included in the 3.5GB listed?
>> 	This question is important to me as I am trying to decide if I
>> should move to a 64-bit system or not.  Losing 500MB bugs me a little
>> more than loosing 256MB.
> That depends, does your video card use shared video memory?  You can
> find that in the BIOS as normally you can adjust that down if you need
> to conserve RAM for non-video needs.
> A lot of laptops do that, but I don't know that all of them do. Mine
> does not, but yours might be different.
> If it's NOT shared memory, then you're only seeing 3.5GB on the 32bit
> system. However, I'd be willing to bet that you ARE using shared memory,
> as typically a 32-bit system sees 3.7 to 3.8GB of RAM our of 4GB.

It doesn't matter if it is shared memory or not.  32 bit systems can only
see a maximum of 4GB ram, and this includes video memory, shared or not.

The difference is that if you move to 64 bit and the video card has its
own ram, you will see a total of about 3.9GB ram.  If it uses shared ram,
you will only see a total of about 3.7GB ram.

Back to the original question, you have 3.5GB of usable ram.  256MB has
been set aside for the video card.  If you move to 64 bit, you will see a
small increase which depends upon whether the video card has its own ram
or uses the shared ram.

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