BleepingComputer.com: Video memory confusion

What's up guys?

I was surfing the web with my little netbook, and I saw on two computer forums that my video card can take up to 512Mb of video memory. Freak, because it says 384mb on acer's website...

My video card is an ATI Mobility Radeon HD 4225.

Acer's website result: http://imageshack.us/photo/my-images/59/capture512mb2.jpg/

Notebookcheck result: http://imageshack.us/photo/my-images/839/capture512mb1.jpg/

PCGen.fr result: http://imageshack.us/photo/my-images/27/capture512mb.jpg/

Bizarre...

Thank you for putting some light in this!

P.S: when I open DXDIAG, it says: Total memory: 1483mb

alpha4345, on 04 August 2011 - 08:16 PM, said:

Hi, alpha.
What does your BIOS detect?

My BIOS are saying nothing about my graphic card. I only have 6 tabs and I can't edit anything about my CPU or GPU (nothing about GPU because there is no GPU tab xD)...

BTW, there is a new BIOS version that I can update to. Should I update? Acer says that it's not recommended if you don't have problems.

<<...I can't edit anything about my CPU or GPU (nothing about GPU because there is no GPU tab xD)...>>

From what I see...your video takes 384MB from your RAM as a default setting, but this can can be increased to 512MB via adjusting the RAM allocated to video in the BIOS.

Louis

hamluis, on 05 August 2011 - 01:59 PM, said:

I cannot edit my allocated RAM. You know, netbooks are really limited with BIOS...

512MB is the maximum possible that the HD 4225 can allocate from system RAM - if there is no setting to alter your netbook's lower value in the BIOS, then I'd say either the specification is fixed at that value, or the amount allocated is determined by the total RAM fitted.

If the specifications for your model of ACER say 384MB video memory, then that would suggest it's a fixed amount. But if for example a total 512MB of RAM was fitted to the unit, I think it unlikely it would still allocate 384MB for video. So I suspect if less RAM is fitted, the allocation reduces, and if the netbook design allows for fitting more RAM than you now have, the video allocation would probably increase.

Interesting... I noticed that the gaming performance increased since I put a 4GB ram... But I mean A LOT (I can play Modern Warfare 2 and Dragon age 2 20-30FPS all settings low).

On my 4GB, my system can only use 2.7GB so I calciulated something (correct me if I'm wrong!):

384+384+512= 1280 / 4GB-1.28GB= ~2.7GB

How did I come to this? Each time that I added 1 GB RAM, the memory allocated to the system was reduced by 384 until I get 4GB. Instead of 384mb, it reduced by 512mb because of it.

I get the great result, but I may be wrong...

This post has been edited by alpha4345: 06 August 2011 - 05:34 AM

So the netbook we're discussing has 4GB of RAM fitted?

The available memory (usually between about 2.5GB and 3.2GB) is governed by how much of the 4GB 32 bit available address space has to be mapped to various hardware devices. e.g. Microsoft's explanation for Vista after SP1:

http://support.microsoft.com/kb/929605

Oh, I was pretty out of the track! (me and my stupid theories!)

But if I upgrade to a 64-bit OS, will I get more video allocated RAM? Because my CPU supports 64-bit OSs...

If its true that my system automatically adjusts my video RAM, I'll be stuck to 384mb because 4GB DDR3 is the maximum amount I can put in this netbook...

Because I have a similar situation with this system, I'll tell you how mine works...self-built system.

XP 32-bit, 8GB RAM (I also dual-boot Win 7 64-bit).

This board has an option for adjusting the RAM allocated to video...I have 3 options in my BIOS under Memory.
a. Maximum...this option was the default setting and reflected 700GB yesterday.
b. 512MB...I elected this option today, personal choice.
c. 384

My useable RAM per any check on both days was 3.2GB...3.25 today, 3.2 yesterday. This si the number reflected via My Computer/Properties.

If your BIOS is set at "max", then the max is based on total RAM recognized within 32-bit O/S, which is yor 384.
If your BIOS is locked and cannot be adjusted at all...the 384 setting is all that you can get.

Unless there is a BIOS update that allows adjustment of your settings...I don't believe that going to a 64-bit O/S will change anything.

I would get different options if I boot into Win 7, 64-bit...because my BIOS allows for such adjustment.

In essence, it sounds to me as if you are locked into that setting without a key for changing it. Netbooks were never intended to be treated in same manner as a system with a normal grouping of BIOS options. It's not only netbooks, but some OEM (HP, Gateway, etc.) systems have the same limitations with BIOS adjustment.

They call it "protecting users from themselves", I call it the price of fueling sales of their products .

Louis

Okay!

Pretty good explanation... My video card is not only avaible on netbooks, many 13.3", 16" and 14" notebooks has it, so it may be changeable with those ones...

A 250mhz graphics overclock may do the job for MW3 xD

alpha4345, on 06 August 2011 - 11:51 AM, said:

Hmm, in theory maybe, but I think probably not.

Changing the OS won't alter the actual video memory allocation, because that's done by the hardware. But in theory, there's no reason why a video driver can't allocate further system memory for itself to use in the same way (e.g. for storing textures), and when video memory is shared system memory anyway, this doesn't have the performance disadvantage it would have compared to a system having much faster dedicated video RAM. Since this further memory allocation would take system memory from the available pool, a 64 bit OS that starts out being able to use all the fitted RAM would feel less effect from the loss.

In practice I doubt whether the mobile chipset video driver would bother with the complication of allocating extra memory, and in any case the netbook might not implement the requirements for the 64 bit OS to use the full 4GB (less the video 384M) of RAM (the support chipset must implement at least an 8GB address space and the BIOS must support relocation of RAM into this address space).

Uhm... So all our theories are turning into the same conclusion: my netbook is stuck at 384MB...

When I bought this little machine, my only intentions were to play games under 2006 and watch 1080p videos, but since I tried MW2, I freaking started to boost it! xD

For 350$, I am not really disappointed about the performance I get!

So thank you everybody who has answered my numerous questions, we can now mark this topic as solved ;)