Ubuntu 12.04 32 Bit sieht mein 8 GB RAM nicht

Ich habe Ubuntu 12.04 32 Bit mit PAE aktivieren.

Linux alptugay-MS-7693 3.2.0-39-generic-pae #62-Ubuntu SMP Wed Feb 27 22:25:11 UTC 2013 i686 athlon i386 GNU/Linux 

Ich habe meinen Computer mit 4 GB RAM verwendet. Die Ausgabe von free -mShows

 total used free shared buffers cached Mem: 3995 1536 2458 0 75 484 

Ich habe jetzt einen weiteren 4 GB RAM hinzugefügt. Welches ist identisch mit dem anderen Widder. Aber Ubuntu sieht es nicht. Die Ausgabe von free hat sich nicht geändert. Aber mein BIOS sieht 8 GB RAM. Auch die Ausgabe von lshwzeigt meine 8 GB RAM:

 *-memory description: System Memory physical id: 27 slot: System board or motherboard size: 8GiB *-bank:0 description: DIMM DDR3 Synchronous 667 MHz (1.5 ns) product: Array1_PartNumber0 vendor: A1_Manufacturer0 physical id: 0 serial: A1_SerNum0 slot: A1_DIMM0 size: 4GiB width: 64 bits clock: 667MHz (1.5ns) *-bank:1 description: DIMM Synchronous [empty] product: Array1_PartNumber1 vendor: A1_Manufacturer1 physical id: 1 serial: A1_SerNum1 slot: A1_DIMM1 *-bank:2 description: DIMM DDR3 Synchronous 667 MHz (1.5 ns) product: Array1_PartNumber2 vendor: A1_Manufacturer2 physical id: 2 serial: A1_SerNum2 slot: A1_DIMM2 size: 4GiB width: 64 bits clock: 667MHz (1.5ns) *-bank:3 description: DIMM Synchronous [empty] product: Array1_PartNumber3 vendor: A1_Manufacturer3 physical id: 3 serial: A1_SerNum3 slot: A1_DIMM3 

Und das ist die Ausgabe von dmidecode

Handle 0x0027, DMI type 16, 23 bytes Physical Memory Array Location: System Board Or Motherboard Use: System Memory Error Correction Type: Multi-bit ECC Maximum Capacity: 32 GB Error Information Handle: Not Provided Number Of Devices: 4  Handle 0x0028, DMI type 19, 31 bytes Memory Array Mapped Address Starting Address: 0x00000000000 Ending Address: 0x0013F0003FF Range Size: 5104 MB Physical Array Handle: 0x0027 Partition Width: 255  Handle 0x0029, DMI type 17, 34 bytes Memory Device Array Handle: 0x0027 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: 667 MHz Manufacturer: A1_Manufacturer0 Serial Number: A1_SerNum0 Asset Tag: A1_AssetTagNum0 Part Number: Array1_PartNumber0 Rank: Unknown Configured Clock Speed: 933 MHz  Handle 0x002A, DMI type 20, 35 bytes Memory Device Mapped Address Starting Address: 0x00000000000 Ending Address: 0x000FFFFFFFF Range Size: 4 GB Physical Device Handle: 0x0029 Memory Array Mapped Address Handle: 0x0028 Partition Row Position: <OUT OF SPEC> Interleave Position: Unknown Interleaved Data Depth: Unknown  Handle 0x002B, DMI type 17, 34 bytes Memory Device Array Handle: 0x0027 Error Information Handle: Not Provided Total Width: Unknown Data Width: 64 bits Size: No Module Installed Form Factor: DIMM Set: None Locator: A1_DIMM1 Bank Locator: A1_BANK1 Type: Unknown Type Detail: Synchronous Speed: Unknown Manufacturer: A1_Manufacturer1 Serial Number: A1_SerNum1 Asset Tag: A1_AssetTagNum1 Part Number: Array1_PartNumber1 Rank: Unknown Configured Clock Speed: Unknown  Handle 0x002C, DMI type 126, 35 bytes Inactive  Handle 0x002D, DMI type 17, 34 bytes Memory Device Array Handle: 0x0027 Error Information Handle: Not Provided Total Width: 64 bits Data Width: 64 bits Size: 4096 MB Form Factor: DIMM Set: None Locator: A1_DIMM2 Bank Locator: A1_BANK2 Type: DDR3 Type Detail: Synchronous Speed: 667 MHz Manufacturer: A1_Manufacturer2 Serial Number: A1_SerNum2 Asset Tag: A1_AssetTagNum2 Part Number: Array1_PartNumber2 Rank: Unknown Configured Clock Speed: 933 MHz  Handle 0x002E, DMI type 20, 35 bytes Memory Device Mapped Address Starting Address: 0x00000000000 Ending Address: 0x000000003FF Range Size: 1 kB Physical Device Handle: 0x002D Memory Array Mapped Address Handle: 0x0028 Partition Row Position: <OUT OF SPEC> Interleave Position: Unknown Interleaved Data Depth: Unknown  Handle 0x002F, DMI type 17, 34 bytes Memory Device Array Handle: 0x0027 Error Information Handle: Not Provided Total Width: Unknown Data Width: 64 bits Size: No Module Installed Form Factor: DIMM Set: None Locator: A1_DIMM3 Bank Locator: A1_BANK3 Type: Unknown Type Detail: Synchronous Speed: Unknown Manufacturer: A1_Manufacturer3 Serial Number: A1_SerNum3 Asset Tag: A1_AssetTagNum3 Part Number: Array1_PartNumber3 Rank: Unknown Configured Clock Speed: Unknown  Handle 0x0030, DMI type 126, 35 bytes Inactive 

Was kann das Problem sein?