Windows 7 - Total available graphics memory?

Asked By Kenny on 21-Feb-09 09:07 AM
What exactly does "Total Graphics Memory: Total available graphics memory of
Approx. 1320MB" actually mean?

Looking at this Sony laptop:

http://www.amazon.co.uk/Sony-Vaio-NS20SS-T6400-DVDRWDL/dp/tech-data/B001PKTGSG/ref=de_a_smtd

Does it mean that 1.32GB of the 3GB installed RAM is used for video?


--
Kenny Cargill




Bruce Chambers replied on 21-Feb-09 11:25 AM
It means that the video adapter can use up to 1.32GB of system RAM, if
necessary, yes.  That would leave the balance for the OS and
applications, which is still probably more than enough for most purposes.


--

Bruce Chambers

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Ian D replied on 21-Feb-09 01:26 PM
That's the maximum memory available to the video.  There's no
way you would use anywhere near that.  Except for dual GPU
cards, there are no PCIe video cards that have more than 1GB.
At that laptop's screen resolution of 1280x800 you probably
would have a minimal amount of memory permanently allocated
to the on-board video, of 128MB - 256MB. You could look up
the specs for the on-board Intel graphics on the Intel web site.

The 1.32GB max is in case you're using a 24" or larger external
LCD in dual monitor mode with the laptop screen, and running
3D games, or other applications that require massive amounts
of texture memory.  Even then it's doubtful you would need
anything near 1.32GB.
Paul replied on 21-Feb-09 02:00 PM
My suspicion would be, that part of the memory is a fixed allocation,
and part is dynamic. DVMT is mentioned here for example. I tried looking
in a few Intel datasheets, but cannot get a clearer picture than
this explanation. Try one of the PDF links on the page, for more
technical words on the subject.

http://www.intel.com/support/graphics/sb/CS-010488.htm

My guess would be, at the hardware level, the static allocation
is programmable at BIOS time, to 256MB or 512MB. That is permanently
stolen from the system, so the OS cannot use that for other purposes
once it boots. Maybe, if you go into the BIOS, there may be a choice
for one value or the other. An Intel datasheet for a "4-series" chip,
suggests 256MB is the default, if the BIOS chooses not to touch the
setting.

So my guess would be 256MB static plus 1024MB dynamic, for a total
of 1320MB. If you're only working in Microsoft Word, then likely
only the 256MB part is in use. If you're playing Crysis, then the
whole 1320MB might be used, if there were enough textures in
usage or whatever.

In other words, don't panic. Only the 256MB is "wasted" :-)

Best guess,
Paul