6 GB RAM is installed, but only 2 GB appears

Hi.
I have a weird problem.
My computer has 6 GB of RAM, but when I turn it on only 1.7 GB of RAM is available. If I run lshw, I can see that the all the RAM is installed. If I restart the system a few times, all the RAM is recognized properly.
Does anyone know the reason for this behavior?

free -m

Code:

---

            total      used      free    shared    buffers    cached
Mem:          1723        690      1033          0        78        231
-/+ buffers/cache:        381      1342
Swap:        9443          0      9443

---

sudo lshw -class memory

Code:

---

  *-firmware             
      descrição: BIOS
      fabricante: American Megatrends Inc.
      physical id: 0
      versão: P1.40
      date: 12/04/2012
      tamanho: 64KiB
      capacidade: 4032KiB
      capabilities: pci upgrade shadowing cdboot bootselect socketedrom edd int13floppy1200 int13floppy720 int13floppy2880 int5printscreen int9keyboard int14serial int17printer acpi usb biosbootspecification
  *-memory
      descrição: Memória do sistema
      physical id: 8
      slot: Placa do sistema ou placa-mãe
      tamanho: 6GiB
    *-bank:0
          descrição: DIMM DDR3 Síncrono 1333 MHz (0,8 ns)
          produto: 9905471-006.A00LF
          fabricante: Kingston
          physical id: 0
          serial: 65206C13
          slot: A1_DIMM0
          tamanho: 4GiB
          largura: 64 bits
          clock: 1333MHz (0.8ns)
    *-bank:1
          descrição: DIMM DDR3 Síncrono 1333 MHz (0,8 ns)
          produto: 9905402-179.A00LF
          fabricante: Kingston
          physical id: 1
          serial: 7E13B005
          slot: A1_DIMM1
          tamanho: 2GiB
          largura: 64 bits
          clock: 1333MHz (0.8ns)
  *-cache:0
      descrição: L1 cache
      physical id: f
      slot: L1 CACHE
      tamanho: 384KiB
      capacidade: 384KiB
      clock: 1GHz (1.0ns)
      capabilities: pipeline-burst internal write-back unified
  *-cache:1
      descrição: L2 cache
      physical id: 10
      slot: L2 CACHE
      tamanho: 3MiB
      capacidade: 3MiB
      clock: 1GHz (1.0ns)
      capabilities: pipeline-burst internal write-back unified

---

uname -a

Code:

---

Linux Principal-sala 3.2.0-36-generic #57-Ubuntu SMP Tue Jan 8 21:44:52 UTC 2013 x86_64 x86_64 x86_64 GNU/Linux

---

So sometimes, after several reboots, all the memory will be grabbed by Ubuntu!

- Could it be a bad connection? Move the RAM cards a little, pull out and push in again and check if it helps.

- Check if you get some error with memtest (that you can start from the grub menu at boot). Run it for a long time, overnight if possible, to catch an error that might show up only once in a while. I suggest that you reboot until your computer (and memtest) will grab all the RAM.

It doesn't look like you're using the 64-bit version of the kernel. The 32-bit version cannot address all six gigabytes unless you have the -pae kernel installed, which uname does not report either.

Try booting from a 64-bit installation CD and run "Try Ubuntu". When it finishes loading, run free again. If you see all your memory, then you should consider upgrading to the 64-bit version.

Quote:

---

Originally Posted by SeijiSensei

It doesn't look like you're using the 64-bit version of the kernel. The 32-bit version cannot address all six gigabytes unless you have the -pae kernel installed, which uname does not report either.

Try booting from a 64-bit installation CD and run "Try Ubuntu". When it finishes loading, run free again. If you see all your memory, then you should consider upgrading to the 64-bit version.

---

But in post #1 [s]he wrote

uname -a

Code:

---

Linux Principal-sala 3.2.0-36-generic #57-Ubuntu SMP Tue Jan 8 21:44:52 UTC 2013 x86_64 x86_64 x86_64 GNU/Linux

---

which indicates a 64-bit kernel (x86_64)

Sorry, I guess I didn't scroll right far enough.

Given that you have to restart a few times to have it detected properly...

Do this: Pay attention to the BIOS memory check screen, and see if it's detected properly there. To make the BIOS screen stay longer, turn off quick memory check. If yes, run Memtest86 whenever you notice the BIOS detecting less RAM than installed.

If no, then I'd suspect either RAM not seated properly, bad RAM, or (sometimes) PSU too weak to drive that many bars of RAM.

If yes, however, it may be a quirk with the firmware. Try upgrading your firmware and see if the problem goes away.

Hi Tuberculo!

I have seen similar situation, and the problem was the sequence of
the memory on the banks, but for this I would recommend you to take a
look at the motherboard manual. if the memory are not placed correct
it can result on bad work.

Eu ja vi algo semelhante a isto e o problema era a sequencia que as
memorias estavam colocadas nos bancos, da uma olhada no site do
fabricante do seu computador na maioria das vezes tem um manual la
com as espicifações. num server que eu estou virando uma versao do
Ubuntu elas estao colocadas com espacos vazios geralmente este bancos
estao diferenciados com cores dois bancos pretos e dois brancos e se v
oce olhar as cores não estão juntas..



Boa sorte
Good luck.

Abraços.

João

Hello,

I had the same problem, only with 4GB. For some reason it would only recognize 2 of the 4. I turned the computer off, unplugged the system, took out the RAM and then put them back in. However, if you have a mixed number like 1*2GB and 1*GB, put the biggest RAM in the first slot.

I say you should definitely consult the manual to your motherboard like Joao Lacerda suggested. Something could be wrong with how they are in or with your BIOS setup. The last thing it could be is that something is wrong with the RAM itself, not with the BIOS or the computer/Ubuntu. I have also read that letting your computer sit for about 5 minutes off with nothing plugged in (PSU) with the RAM out sort of resets it, so you could try that too.

What kind of motherboard is it? Look at this if not sure:

Code:

---

sudo dmidecode

---

It's always best to use RAM on the mobo vendor's list (though this is not always feasible) and use RAM in matched pairs.

Thanks for all the replies.
I have already tried memtest, but I did not run it for a long time, I'll try that later.
If I want, I always manage to have 6 GB of RAM, but I have to reboot a few times. That's annoying. I think the problem may be in Ubuntu because, in BIOS, all the memory is recognized every time. The command lshw also recognizes 6 GB.
My motherboard is A55M-HVS. There are only two banks. I have already switched positions, with no result. I also tried BIOS update.
I will try Lightning Dragon's idea later.

dmidecode:

Code:

---

# dmidecode 2.11
SMBIOS 2.7 present.
19 structures occupying 1146 bytes.
Table at 0x000E9690.

Handle 0x0000, DMI type 0, 24 bytes
BIOS Information
        Vendor: American Megatrends Inc.
        Version: P1.40
        Release Date: 12/04/2012
        Address: 0xF0000
        Runtime Size: 64 kB
        ROM Size: 4096 kB
        Characteristics:
                PCI is supported
                BIOS is upgradeable
                BIOS shadowing is allowed
                Boot from CD is supported
                Selectable boot is supported
                BIOS ROM is socketed
                EDD is supported
                5.25"/1.2 MB floppy services are supported (int 13h)
                3.5"/720 kB floppy services are supported (int 13h)
                3.5"/2.88 MB floppy services are supported (int 13h)
                Print screen service is supported (int 5h)
                8042 keyboard services are supported (int 9h)
                Serial services are supported (int 14h)
                Printer services are supported (int 17h)
                ACPI is supported
                USB legacy is supported
                BIOS boot specification is supported
                Targeted content distribution is supported
                UEFI is supported
        BIOS Revision: 4.6

Handle 0x0001, DMI type 1, 27 bytes
System Information
        Manufacturer: To Be Filled By O.E.M.
        Product Name: To Be Filled By O.E.M.
        Version: To Be Filled By O.E.M.
        Serial Number: To Be Filled By O.E.M.
        UUID: 03000200-0400-0500-0006-000700080009
        Wake-up Type: Power Switch
        SKU Number: To Be Filled By O.E.M.
        Family: To Be Filled By O.E.M.

Handle 0x0002, DMI type 2, 15 bytes
Base Board Information
        Manufacturer: ASRock
        Product Name: A55M-HVS
        Version:                     
        Serial Number:                     
        Asset Tag:                     
        Features:
                Board is a hosting board
                Board is replaceable
        Location In Chassis:                     
        Chassis Handle: 0x0003
        Type: Motherboard
        Contained Object Handles: 0

Handle 0x0003, DMI type 3, 22 bytes
Chassis Information
        Manufacturer: To Be Filled By O.E.M.
        Type: Desktop
        Lock: Not Present
        Version: To Be Filled By O.E.M.
        Serial Number: To Be Filled By O.E.M.
        Asset Tag: To Be Filled By O.E.M.
        Boot-up State: Safe
        Power Supply State: Safe
        Thermal State: Safe
        Security Status: None
        OEM Information: 0x00000000
        Height: Unspecified
        Number Of Power Cords: 1
        Contained Elements: 0
        SKU Number: To be filled by O.E.M.

Handle 0x0004, DMI type 9, 17 bytes
System Slot Information
        Designation: PCI1
        Type: 32-bit PCI
        Current Usage: In Use
        Length: Short
        ID: 1
        Characteristics:
                3.3 V is provided
                Opening is shared
                PME signal is supported

Handle 0x0005, DMI type 9, 17 bytes
System Slot Information
        Designation: PCIE2
        Type: x16 PCI Express
        Current Usage: In Use
        Length: Short
        ID: 17
        Characteristics:
                3.3 V is provided
                Opening is shared
                PME signal is supported
        Bus Address: 0000:00:02.0

Handle 0x0006, DMI type 9, 17 bytes
System Slot Information
        Designation: PCIE3
        Type: x4 PCI Express
        Current Usage: In Use
        Length: Short
        ID: 18
        Characteristics:
                3.3 V is provided
                Opening is shared
                PME signal is supported
        Bus Address: 0000:00:04.0

Handle 0x0007, DMI type 11, 5 bytes
OEM Strings
        String 1: To Be Filled By O.E.M.

Handle 0x0008, DMI type 16, 23 bytes
Physical Memory Array
        Location: System Board Or Motherboard
        Use: System Memory
        Error Correction Type: None
        Maximum Capacity: 6 GB
        Error Information Handle: Not Provided
        Number Of Devices: 2

Handle 0x0009, DMI type 19, 31 bytes
Memory Array Mapped Address
        Starting Address: 0x00000000000
        Ending Address: 0x0017FFFFFFF
        Range Size: 6 GB
        Physical Array Handle: 0x0008
        Partition Width: 255

Handle 0x000A, DMI type 17, 34 bytes
Memory Device
        Array Handle: 0x0008
        Error Information Handle: Not Provided
        Total Width: 64 bits
        Data Width: 64 bits
        Size: 4096 MB
        Form Factor: DIMM
        Set: None
        Locator: A1_DIMM0
        Bank Locator: A1_BANK0
        Type: DDR3
        Type Detail: Synchronous
        Speed: 1333 MHz
        Manufacturer: Kingston       
        Serial Number: 65206C13 
        Asset Tag: A1_AssetTagNum0
        Part Number: 9905471-006.A00LF
        Rank: 2
        Configured Clock Speed: 533 MHz

Handle 0x000B, DMI type 20, 35 bytes
Memory Device Mapped Address
        Starting Address: 0x00000000000
        Ending Address: 0x000FFFFFFFF
        Range Size: 4 GB
        Physical Device Handle: 0x000A
        Memory Array Mapped Address Handle: 0x0009
        Partition Row Position: 1

Handle 0x000C, DMI type 17, 34 bytes
Memory Device
        Array Handle: 0x0008
        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: DDR3
        Type Detail: Synchronous
        Speed: 1333 MHz
        Manufacturer: Kingston       
        Serial Number: 7E13B005 
        Asset Tag: A1_AssetTagNum1
        Part Number: 9905402-179.A00LF
        Rank: 1
        Configured Clock Speed: 533 MHz

Handle 0x000D, DMI type 20, 35 bytes
Memory Device Mapped Address
        Starting Address: 0x00100000000
        Ending Address: 0x0017FFFFFFF
        Range Size: 2 GB
        Physical Device Handle: 0x000C
        Memory Array Mapped Address Handle: 0x0009
        Partition Row Position: 1

Handle 0x000E, DMI type 32, 20 bytes
System Boot Information
        Status: No errors detected

Handle 0x000F, DMI type 7, 19 bytes
Cache Information
        Socket Designation: L1 CACHE
        Configuration: Enabled, Not Socketed, Level 1
        Operational Mode: Write Back
        Location: Internal
        Installed Size: 384 kB
        Maximum Size: 384 kB
        Supported SRAM Types:
                Pipeline Burst
        Installed SRAM Type: Pipeline Burst
        Speed: 1 ns
        Error Correction Type: Multi-bit ECC
        System Type: Unified
        Associativity: 2-way Set-associative

Handle 0x0010, DMI type 7, 19 bytes
Cache Information
        Socket Designation: L2 CACHE
        Configuration: Enabled, Not Socketed, Level 2
        Operational Mode: Write Back
        Location: Internal
        Installed Size: 3072 kB
        Maximum Size: 3072 kB
        Supported SRAM Types:
                Pipeline Burst
        Installed SRAM Type: Pipeline Burst
        Speed: 1 ns
        Error Correction Type: Multi-bit ECC
        System Type: Unified
        Associativity: 16-way Set-associative

Handle 0x0012, DMI type 4, 42 bytes
Processor Information
        Socket Designation: CPUSocket
        Type: Central Processor
        Family: S-Series
        Manufacturer: AMD
        ID: 10 0F 30 00 FF FB 8B 17
        Signature: Family 18, Model 1, Stepping 0
        Flags:
                FPU (Floating-point unit on-chip)
                VME (Virtual mode extension)
                DE (Debugging extension)
                PSE (Page size extension)
                TSC (Time stamp counter)
                MSR (Model specific registers)
                PAE (Physical address extension)
                MCE (Machine check exception)
                CX8 (CMPXCHG8 instruction supported)
                APIC (On-chip APIC hardware supported)
                SEP (Fast system call)
                MTRR (Memory type range registers)
                PGE (Page global enable)
                MCA (Machine check architecture)
                CMOV (Conditional move instruction supported)
                PAT (Page attribute table)
                PSE-36 (36-bit page size extension)
                CLFSH (CLFLUSH instruction supported)
                MMX (MMX technology supported)
                FXSR (FXSAVE and FXSTOR instructions supported)
                SSE (Streaming SIMD extensions)
                SSE2 (Streaming SIMD extensions 2)
                HTT (Multi-threading)
        Version: AMD A6-3500 APU with Radeon(tm) HD Graphics
        Voltage: 1.4 V
        External Clock: 100 MHz
        Max Speed: 2100 MHz
        Current Speed: 2100 MHz
        Status: Populated, Enabled
        Upgrade: Socket FM1
        L1 Cache Handle: 0x000F
        L2 Cache Handle: 0x0010
        L3 Cache Handle: Not Provided
        Serial Number: Not Specified
        Asset Tag: Not Specified
        Part Number: Not Specified
        Core Count: 3
        Core Enabled: 3
        Thread Count: 3
        Characteristics:
                64-bit capable

Handle 0x0013, DMI type 127, 4 bytes
End Of Table

---