Slightly different memory question

[Mark Haney]

Jason Crain wrote:
> 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.


<sarcasm>Really?  I had no idea.</sarcasm>  And for the purposes of this
discussion, irrelevant.  He's aware of the fact that 32-bit systems can
only see 4GB.


> 
> 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.
> 

Isn't that exactly what I said?

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Mark Haney
Sr. Systems Administrator
ERC Broadband
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