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Message 1 of 11 (9,402 Views)

T400 Vista only 2.5G of RAM showing

I have had 3G and 4G of RAM installed in this T400.  Control Panel->System shows the correct amount of physical RAM in either case.  Either way, Task Manager only shows 2.5G total.  I understand that the 4G address space gets consumed to some extent by device mappings (or potential device mappings) including the discrete graphics.  And that the chipset graphics grab some actual RAM.

However, even with both of those a max of 2.5G is ridiculous.  Especially with 4G installed.

(My T61 makes all 3G available, and my deskside with 4G installed still makes 3.5 avaiable) 

Any ideas on how to improve this?  Any hope of BIOS mods, different chipset drivers, ???

I bought this thing because it had switchable graphics and an XP downgrade - unfortunately the sales person didn't tell me that they weren't compatible - and because it could take 4G of RAM, since I need to run some virtual machines that need RAM.

Grrr.

 


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Message 2 of 11 (9,392 Views)

Re: T400 Vista only 2.5G of RAM showing

since the T400 has switchable GPUs, the second GPU is using up an additional 512MB of address space.   2.5GB of available memory sounds normal for your system.

 

unfortunately this is a limitation of 32-bit architecture and not something that can be fixed in the BIOS.   the only way to use a 32-bit OS and address all 4GB is to use windows server 2003 or 2008.   they support a feature called "memory hoisting" and can move addresses above the 4GB mark to regain memory for use by your OS.   individual applications will still be limited to 2GB each, however.

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Message 3 of 11 (9,364 Views)

Re: T400 Vista only 2.5G of RAM showing

Hello,

 

how much physical memory is shown in taskmanager?

 

Kind regards

Andreas

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Message 4 of 11 (9,329 Views)

Re: T400 Vista only 2.5G of RAM showing

[ Edited ]

Hmmm, I think I said somewhere that Task manager shows 2.5G Smiley Happy

 

To Erik: my comment about BIOS changes comes from the spec that says:  ATI Mobility Radeon with 256MB, and an assumption (!) that the chipset graphics doesn't need more actual RAM than that.  .5G of address space and actual RAM seems like plenty to me, particularly when the address space can come from above the 3G RAM installed. One could hope that BIOS or other changes could limit the address space used to the actual amount required - or desired.  It would also help if Microsoft would go back to supporting PAE and require driver writers (particularly w/a new environment like Vista) to do the same.

It's mostly just frustrating that one doesn't discover these things until too late Smiley Sad  I'm well aware of the limitations of 32 bit operating systems, at least since XP SP2, but didn't expect such a big hit, given what I see on my other machines.

Thanks for the replies,

Z.

Message Edited by zoltanthegypsy on 10-01-2008 06:44 AM

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Message 5 of 11 (9,317 Views)

Re: T400 Vista only 2.5G of RAM showing

Hello,

 

that aren´t good news. I ask specifically for physical, you don´t mentioned explicitly.

 

Seems that W serie also have problems with recognising more than 2GB.

Strange my R60 with PAE will see min. 3,4 I think.

 

Hopefully we´ll get more information on this.

 

Regards

Andreas

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Message 6 of 11 (9,315 Views)

Re: T400 Vista only 2.5G of RAM showing

the ATI card has 256MB physical and can use up to 256MB of your system memory, hence the extra 512MB being taken up.   all of that needs address space and that space has to come from the 0~3GB block since the 3~4GB block has already been allocated.

 

i have 16GB in my thinkstation and on any given day only have about 9 to 11GB free.   the quadro FX 3700 takes up 512MB of address space plus 2GB physical memory, on top of everything else requiring address space.

 

unfortunately it's all about the addressing and not so much about the bit architecture, even though 32-bit systems are quite a bit more limited than 64-bit.

 

i agree that the subject is a bit frustrating.   the same thing happened 13 years ago when we transitioned from 16- to 32-bit OSes and will happen again when we go from 64-bit to 128-bit.   it'll be funny when people start complaining because they can only use 2TB of memory with their laptops because of the 64-bit limitation. Smiley Wink

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Message 7 of 11 (9,269 Views)

Re: T400 Vista only 2.5G of RAM showing

Andreas,

System in control panel shows the correct physical memory - either 3 or 4G depending on what's installed.  I don't find the term "physical" referenced in Task Manager on Vista, just "total", which is 2.5G.    Which is the total physical available AFAICS Smiley Sad

Erik,

Thanks for the info on the ATI card.  Know of any way to suppress its use of system RAM?  I'm looking, but haven't found it yet.  For that matter, I wonder if disabling it or the chipset graphics in BIOS would free some RAM.  (?)   This is going to be a serious issue when running VMWare clients on this laptop.

My T61 does a really nice job running Linux and Solaris clients for code development, but has really crappy battery life even w/the 7 cell battery.  The T400 _should_ have been the answer to this...

(and while I'm ranting, I can't imagine that blocking out the entire 3-4G address space was anything other than lazyness on the part of the designers.  Actually selling me the useless RAM makes me a little cranky too...)

Thanks,

Z


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Message 8 of 11 (9,260 Views)

Re: T400 Vista only 2.5G of RAM showing

[ Edited ]

Is it bad manners to answer a few of my own questions?  I've been swapping memory sticks in and out and toggling BIOS between discrete and integrated graphics with switchable graphics and detection disabled.  Some interesting numbers regarding available RAM and (very rough) power consumption/battery life:

 

Baseline:  Switchable graphics enabled, either 3G or 4G of RAM installed:  total in Task Manager/performance -> 2517MB.

Switchable graphics disabled, 3G RAM: integrated graphics -> still 2517MB, discrete graphics -> 2553MB.  oh boy!

Switchable graphics disabled, 4G RAM: integrated graphics -> 3029MB, discrete graphics -> 3065MB.  better!

 

Power consumption/battery life w/9cell, just desktop and a vim window open, 95% charge: integrated graphics ->6:30, discrete graphics -> varied from 4:30 to 5:30.  Looks like ATI has some kind of adaptive power thing going on.

 

 Switching to integrated graphics only in BIOS required a boot to let the driver (re)install, then a reboot to get back to a useful system with correct resolution. -- On further experimentation, it looks like the double boot to switch to intel integrated graphics only happens when done along with a RAM size change.  Need to test that further.

 

So, it is possible to stretch the available RAM by shutting off one of the graphics units and stuffing in 4G of RAM.  It's a little expensive and feels wasteful, but the bump for switchable was only $75US.  I imagine I'll run this thing w/4G RAM and only the Intel integrated graphics turned on unless I have some presentation thing going on that requires the fancy graphics controller (not likely for this elderly hardware nerd).

 

Maybe the above will be useful to someone.  Please correct any typos, thinkos, or factual errors.  I'll get around to posting this @ www.beezmo.com one of these days along with some other thinkpad notes.

 

Now I've go to go screw down the palm rest...

Message Edited by zoltanthegypsy on 10-01-2008 02:36 PM
Message Edited by zoltanthegypsy on 10-01-2008 02:39 PM
Message Edited by zoltanthegypsy on 10-01-2008 02:49 PM

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Message 9 of 11 (9,242 Views)

Re: T400 Vista only 2.5G of RAM showing


zoltanthegypsy wrote:

Is it bad manners to answer a few of my own questions?


answering q's on your own is a great way to learn.   it looks like you've figured everything out, too, before i had a chance to reply.

 

thanks for the update on everything.   if the same question comes up in the future then we have this thread for reference.

 

good job Smiley Wink

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Message 10 of 11 (5,981 Views)

Re: T400 Vista only 2.5G of RAM showing

I don't know how, exactly, but while fiddling around with the BIOS graphics settings this morning and doing several cold reboots, I was able to get the system to come up showing 3 GB  (3,015 MB) of physical memory while switchable graphics is supposedly running (ATI control panel comes up, and shows monitors 3 and 4 being active - instead of the Intel GMA's monitors 1 and 2).

 

I went to the BIOS and first turned off auto-switchable graphics and changed the graphics to the discrete graphics.  After a reboot, physical memory only reported 2,553 MB (as you've seen), so i decided to change back.  I shutdown, then F1 into the BIOS, and set the display to switchable graphics (and turned auto-switchable back on).

 

After booting into VB32, I now show 3,015 MB. 

TP shows 3GB

http://farm5.static.flickr.com/4011/4385405294_4404ec6339_o.png

 

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