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Yesterday I bought a new laptop with 4GB RAM. When I installed Ubuntu 11.10 (beta) it is showing 1.5GiB (2GB-512MB graphics) ignoring the 2GB.

uname -a:

Linux js 3.0.0-11-generic-pae #17-Ubuntu SMP Fri Sep 9 19:38:01 UTC 2011 i686 athlon i386 GNU/Linux

dmidecode:

# dmidecode 2.9
SMBIOS 2.7 present.

Handle 0x0016, DMI type 16, 23 bytes
Physical Memory Array
Location: System Board Or Motherboard
Use: System Memory
Error Correction Type: None
Maximum Capacity: 8 GB
Error Information Handle: Not Provided
Number Of Devices: 2

Handle 0x0018, DMI type 17, 34 bytes
Memory Device
Array Handle: 0x0016
Error Information Handle: Not Provided
Total Width: 64 bits
Data Width: 64 bits
Size: 2048 MB
Form Factor: DIMM
Set: None
Locator: A1_DIMM0
Bank Locator: A1_BANK0
Type: <OUT OF SPEC>
Type Detail: Synchronous
Speed: 1333 MHz (0.8 ns)
Manufacturer: Samsung         
Serial Number: 7943CECA  
Asset Tag: A1_AssetTagNum0
Part Number: M471B5773DH0-CH9  

Handle 0x001A, DMI type 17, 34 bytes
Memory Device
Array Handle: 0x0016
Error Information Handle: Not Provided
Total Width: 64 bits
Data Width: 64 bits
Size: 2048 MB
Form Factor: DIMM
Set: None
Locator: A1_DIMM1
Bank Locator: A1_BANK1
Type: <OUT OF SPEC>
Type Detail: Synchronous
Speed: 1333 MHz (0.8 ns)
Manufacturer: Undefined       
Serial Number: 00000002  
Asset Tag: A1_AssetTagNum1
Part Number: V01D3S82GB26826813

Update

When I revisited SHOP salesguy replaced RAM, now everything works fine. The problem is Defective RAM (unknown brand) included on laptop upgrade (came with 2GB).

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Manufacturer: Undefined Serial Number: 00000002 This troubles me. –  nickguletskii Sep 13 '11 at 13:53
    
@sridher - open up the cover hiding the RAM DIMMs- are they of the same type or different manufacturers? In your BIOS do you have any memory options to play with? Have you done a memory test when booting from the Live CD? –  fossfreedom Sep 13 '11 at 14:03
    
@fossfreedom - they are from different manufacturers, in bios it showing correctly 2+2 = 4GB. i tried the live cd but same. –  Sridher Sep 13 '11 at 14:23
1  
hmmm - I would take it back to the shop and insist you have memory from the same manufacturer. Double check with a 10.04/11.04 Live USB/CD to see if this is a new bug with 11.10 - if lucid or natty show the same - then go back to the shop... –  fossfreedom Sep 13 '11 at 14:29
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closed as off topic by htorque, jrg, Marco Ceppi Sep 16 '11 at 14:54

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3 Answers

Check in the BIOS if it recognizes those 4GB, if not, then you have to check if they are right in the memory slot, and check if those memories are indeed 4GB in total (could be just one or two memory cards).

If BIOS recognize 4 GB then.. are you using a 32 or 64 bit version of Ubuntu, if you want to use a large amount of memory in your computer use a 64 bit operating system.

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in bois it is detecting 4GB,for 4GB memory support i already installed PAE kernel on 32bit Ubuntu –  Sridher Sep 13 '11 at 14:32
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converted my comment into answer

Double check with a 10.04/11.04 Live USB/CD to see if this is a new bug with 11.10. If lucid or natty show the same - then go back to the shop...

It does look like in your trace that the RAM is partially defective - especially since the first DIMM is of a known manufacturer - but the second is unknown.

I would take it back to the shop and insist you have memory from the same manufacturer.

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Have you already tried with the PAE (Physical Address Extension)? Actually 4GB shouldn't be a problem...

Anyway, try this:

sudo apt-get install linux-generic-pae linux-headers-generic-pae
sudo reboot now

I had the same problem, and after installing the linux-generic-pae and linux-headers-generic-pae my Ubuntu shows the whole 8GB I have available.

I hope it helps :-)

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