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BIOS not recognizing 4GB

Posted: Sun Jan 10, 2010 2:08 am
by me61ic
Hi there everybody, I have succesfully upgraded my Vaio VGN-AR31M with Phoenix BIOS version, R0200J6, from Vista 32bits to Windows 7 64 bits. I wanted to upgrade as I do a lot of video editing with my machine and I want to take all that the processor can give out of my Vaio.
I think I did a lot of research before proceeding.

First of all I wanted to upgrade the RAM of the machine to 4GB but I saw in the SONY support pages that the maximum RAM available for this notebook was 2GB. I then came across this link where some people say they have successfully upgraded the RAM for a Vaio AR-41 to 4gb using 2 Kingston DDR2 667: ... e-4gb-ram/
Went on and bought the 2 RAM memories here: ... EMF-2G.htm

Installed them while still using Vista Home Premium 32bits and it was showing 4GB through Panel Control -> System, everything was working as intended, I knew the system was showing that, even though it was really only using 3GB. I could verify this using Everest Corporate Edition.

Now in Windows 7 Home Premium 64 bits, I go to Control Panel -> System, and it shows 4GB (3GB usable). I could also verify this using Everest Corporate Edition. I have entered the Phoenix BIOS version R0200J6 and it shows the same and doesn’t let me modify in any way to 4GB of RAM.

I have followed the instructions on this link ... 5&tstart=0
and I have edited the BIOS to allow virtualization in my machine, but it still shows RAM 4GB (3GB usable).

I also came accross this link:
and have followed the instructions, made the changes, but it still only uses 3 GB.

Any ideas how to proceed? Many thanks in advance

Re: BIOS not recognizing 4GB

Posted: Thu Jan 14, 2010 2:07 pm
by me61ic
Nobody, really?
Thanks anyway

Re: BIOS not recognizing 4GB

Posted: Wed Mar 17, 2010 10:32 am
by biosdude
What do you exactly want? You want 4GB reported as Usable?
If yes then you need a technical answer here :) read further

Your laptop uses Intel Core 2 Duo. This CPU is 64-bit addressing capacity. Since you are using Windows 7 64-bit, you should see 4G memory without issues.
However right below 4G memory boundary, the systems PCI MMIO, PCI-Express MMIO and possibly the Integrated Video / Graphics Engine's Video Buffer etc etc will take more then 700MB of memory. In your laptop's case it looks like all of them together takes 1GB.

Sounds wierd isnt it? But Intel/Sony knows it is not pleasant for a customer. So they have something called Memory Reclaim (search for "Memory Remap", "Memory Reclaim" or "Max Memory" etc). Play around these configurations. This will let customer to map the actual physical memory from 3G to 4G to some address above 4G. This will work as long as you enable PAE in OS or use a 64-bit OS.

Good luck and please report your results so that it may benefit somebody else too


Re: BIOS not recognizing 4GB

Posted: Thu Apr 15, 2010 7:46 pm
by me61ic
Thanks a lot for replying.

To tell you the truth I don't really understand how to perform what you hint me to do.

My main problem is that I think my computer is only using 3GB of RAM although it has 2x2GB modules installed, I have read that Sony doesn't let upgrading RAM on my computer VGN-AR31M above 2GB as they want you to buy newer computers... As I have read the limitation is done though the BIOS, but once I enter the BIOS I can pretty much change NOTHING in there, there are no options for anything appart from boot sequence and time. That is why I would like to modify the Phoenix BIOS somehow to let the computer use the whole upgraded 4GB of RAM

I have also noticed that I am not able to resume from hibernation mode with the 4GB of RAM and that the nice start up animation flying logo of Windows 7 does not appear, I get the Vista green bar instead when the 4GB are installed, but amazingly, when the older RAM modules (2x1GB) are installed both the hibernation + the start up animation flying logo works perfectly.

I would like to be able to alter the BIOS somehow to solve all this anoying behaviour.

Thanks again.

Re: BIOS not recognizing 4GB

Posted: Sat May 15, 2010 8:20 pm
by edwin
For hibernation to work properly I think you need to recreate the hibernation file on disk which is now only 2GB in size from your previous set of memory. How much disk space is still free?

Re: BIOS not recognizing 4GB

Posted: Fri Jul 15, 2011 12:15 pm
by neo88
I have just buy memory DD2 PC6400. 2 GB@ 2pc with the same chipset for installed to my Laptop Byon P2301 G/D with hope can run Dual channel.
But when installed on my laptop, i only see windows XP Logo & progress bar... then the LCD become blank...
(its not hang, just because i still can see my hardisk lamp indicator blinking, and when i push off button they still work to shut down normaly, even i cant see anything on screen)
When i just installed 2 GB @ 1 pc the windows XP run normal,
this is not about memory stick problem, because i have try to changes n test with mem86x is normal,

I suppose that error from my BIOS that need to upgrade,
because i only see 3317 MB when counting on booting, but when i see on BIOS set up is read "slot 0: 2048 GB slot 1:2048 GB 4GB (Dual Channel)"

where can i find Phoenix bios update?
or is there any solution for my laptop/notebook to recognizing 4GB installed ?

My Laptop/notebook BYON (Local brand) specification
Laptop P2301 G/D Intel core 2 CPU T7200 @ 2.00 GHz
OS : Windows XP SP 2

here is i use to detect my bios :
BIOS Type: Phoenix
BIOS Date: December 22nd 2006
BIOS ID: Ver 1.00PARTTBLx-None
Chipset: Intel 27A0 rev 3
SuperIO: Unknown
Manufacturer: Intel Corporation
Motherboard: Calistoga & ICH7M Chipset
[X] A BIOS Update has been detected for your PC.

Need help as soon as possible

Re: BIOS not recognizing 4GB

Posted: Fri Jul 15, 2011 3:29 pm
by edwin
Your onboard video + PCIexpress slots are taking much of the memory. It can be you can set everything to show 4GB usable but the question is if you really want that. In windows you can use 4GB, right?

Re: BIOS not recognizing 4GB

Posted: Sat Jul 16, 2011 11:55 am
by neo88
Yes, my VGA is on board. How do you know that my video + PCI express slot taking much of memory ? How can i check it n fix it?

Yes, i really want that i still can use/run my XP sp 2 with 2 GB@ 2 pc memory installed on my laptop (4GB).

just to inform that i have already try to booting with linux, had the same output ---> lcd become blank.
so i try to booting with windows xp setting vga enable 640x480, lcd still blank.
but when i try to booting with mini linux 640x480 the windows xp run normaly.

what do you suggest to solve my problem ?

Re: BIOS not recognizing 4GB

Posted: Sat Jul 16, 2011 2:43 pm
by edwin ... ook&p_id=2
has 945GM chipset

945GM supports 4GB:

You are already using the latest version of the bios and Byon says this laptop can handle 2x 1GB maximum for 2GB total. So I think they used the 845GMS chipset that only support 2GB maximum, calling it a 845GM series chipset. Nothing much you can do about this, other than buy a new laptop.

Re: BIOS not recognizing 4GB

Posted: Sun Jul 17, 2011 10:14 am
by neo88
Thank you bro Edwin for your support,

I know that byon website n manual byon book tell that my laptop has only max 2GB installed memory.
But when i was check with sisoftsandra software its read Max 3 GB i checked it with biosagent366 is read the same value Max 3072 MB (3 GB)
so.. i didnt believe what vendor Byon say (max only 2GB or 3GB). I had browsing n cek it my intel chipset on intel website before u inform it to me...
what i was found, its like i was thinking that my chipset is support to 4GB, :

Mobile Intel® 945GM/GME Express Chipset
System Memory Support
• Supports single-/dual-channel DDR2 SDRAM
• Maximum Memory supported: up to 4 GB at 400, 533 and 667 MHz
• 64-bit wide per channel
• Three Memory Channel Configurations supported:
— Single-Channel
— Dual-Channel Symmetric
— Dual-Channel Asymmetric

And it's make sanse to me, because i ready try to put only 2GB @ 1pc installed on bank 0 is working, another try to put on bank 1 is working too.
Here is the another people who have the same problem like me (having then same phoenix bios) but on Sony Vaio laptop ... e-4gb-ram/
The Sony vendor said that Vaio vgn ar41s only have max 2GB installed memory, here is the specification vaio ar41s

I think the solution only is to update bios
Version du BIOS/Date Phoenix Technologies LTD R0030J8, 23/05/2007
Version SMBIOS 2.4

so, its just BIOS Limitations, i dont know why they do this,
unfortunately, i can'f find bios date 23/05/2007 for my laptop

Re: BIOS not recognizing 4GB

Posted: Wed Aug 31, 2011 10:19 am
by edwin
It is not just the bios that can limit the maximum memory but the hardware itself too. That this chipset can be fitted with 4GB if properly implemented doesn't mean automatically it will always do this.

Re: BIOS not recognizing 4GB

Posted: Wed Aug 31, 2011 7:58 pm
by gabiz_ro
Intel 945 chipset support max 4GB of RAM but usable are less sometime,depends of system manufacturer ~3.25GB usable
From 3.25GB to 4GB are system resources.

Re: BIOS not recognizing 4GB

Posted: Wed Aug 31, 2011 9:48 pm
by edwin
That is in 32bit windows. We are still talking hardware here so before any operating system. If you use 64bit windows will see the full 4GB.

BIOS not recognizing 4GB

Posted: Tue May 15, 2012 1:58 pm
by jin1234i
Your motherboard should be able to support up to 4GB of memory. If your BIOS is not recognizing it.not support bios to 4GB .