I've installed 8GB of RAM (2x4GB) in my computer. Before I have only 4GB (1x4GB), and I've installed the new cards one where the oldest was and the other in the other slot of the same type. But if I check my Ubuntu's details or htop, it only shows 4GB (3'8GB). My motherboard is Asus P7H55-M. In windows it detects 8GB but it says that it only can use 4GB, don't know why. This are my outputs. (there are in spanish)
free -h:
total usado libre compart. búffers almac.
Mem: 3,8G 2,2G 1,6G 18M 119M 869M
-/+ buffers/cache: 1,2G 2,6G
Intercambio: 4,5G 0B 4,5Gsudo dmidecode --type memory:
SMBIOS 2.6 present.
Handle 0x0008, DMI type 5, 24 bytes
Memory Controller Information Error Detecting Method: 64-bit ECC Error Correcting Capabilities: None Supported Interleave: One-way Interleave Current Interleave: One-way Interleave Maximum Memory Module Size: 2048 MB Maximum Total Memory Size: 8192 MB Supported Speeds: Other Supported Memory Types: DIMM SDRAM Memory Module Voltage: 3.3 V Associated Memory Slots: 4 0x0009 0x000A 0x000B 0x000C Enabled Error Correcting Capabilities: None
Handle 0x0009, DMI type 6, 12 bytes
Memory Module Information Socket Designation: DIMM0 Bank Connections: 0 1 Current Speed: Unknown Type: DIMM SDRAM Installed Size: 4096 MB (Double-bank Connection) Enabled Size: 4096 MB (Double-bank Connection) Error Status: OK
Handle 0x000A, DMI type 6, 12 bytes
Memory Module Information Socket Designation: DIMM1 Bank Connections: 2 3 Current Speed: Unknown Type: DIMM SDRAM Installed Size: Not Installed Enabled Size: Not Installed Error Status: OK
Handle 0x000B, DMI type 6, 12 bytes
Memory Module Information Socket Designation: DIMM2 Bank Connections: 4 5 Current Speed: Unknown Type: DIMM SDRAM Installed Size: 4096 MB (Double-bank Connection) Enabled Size: 4096 MB (Double-bank Connection) Error Status: OK
Handle 0x000C, DMI type 6, 12 bytes
Memory Module Information Socket Designation: DIMM3 Bank Connections: 6 7 Current Speed: Unknown Type: DIMM SDRAM Installed Size: Not Installed Enabled Size: Not Installed Error Status: OK
Handle 0x0036, DMI type 16, 15 bytes
Physical Memory Array Location: System Board Or Motherboard Use: System Memory Error Correction Type: None Maximum Capacity: 16 GB Error Information Handle: Not Provided Number Of Devices: 4
Handle 0x0038, DMI type 17, 28 bytes
Memory Device Array Handle: 0x0036 Error Information Handle: Not Provided Total Width: 64 bits Data Width: 64 bits Size: 4096 MB Form Factor: DIMM Set: None Locator: DIMM0 Bank Locator: BANK0 Type: DDR Type Detail: Synchronous Speed: 1333 MHz Manufacturer: Manufacturer0 Serial Number: SerNum0 Asset Tag: AssetTagNum0 Part Number: PartNum0 Rank: Unknown
Handle 0x003A, DMI type 17, 28 bytes
Memory Device Array Handle: 0x0036 Error Information Handle: Not Provided Total Width: Unknown Data Width: Unknown Size: No Module Installed Form Factor: DIMM Set: None Locator: DIMM1 Bank Locator: BANK1 Type: Unknown Type Detail: Unknown Speed: Unknown Manufacturer: Manufacturer1 Serial Number: SerNum1 Asset Tag: AssetTagNum1 Part Number: PartNum1 Rank: Unknown
Handle 0x003C, DMI type 17, 28 bytes
Memory Device Array Handle: 0x0036 Error Information Handle: Not Provided Total Width: 64 bits Data Width: 64 bits Size: 4096 MB Form Factor: DIMM Set: None Locator: DIMM2 Bank Locator: BANK2 Type: DDR Type Detail: Synchronous Speed: 1333 MHz Manufacturer: Manufacturer2 Serial Number: SerNum2 Asset Tag: AssetTagNum2 Part Number: PartNum2 Rank: Unknown
Handle 0x003E, DMI type 17, 28 bytes
Memory Device Array Handle: 0x0036 Error Information Handle: Not Provided Total Width: Unknown Data Width: Unknown Size: No Module Installed Form Factor: DIMM Set: None Locator: DIMM3 Bank Locator: BANK3 Type: Unknown Type Detail: Unknown Speed: Unknown Manufacturer: Manufacturer3 Serial Number: SerNum3 Asset Tag: AssetTagNum3 Part Number: PartNum3 Rank: UnknownWith dmicoded it shows that there are two RAMs of 4GB.
And, obviously I'm using a 64bits kernel:
Linux m0skva 3.13.0-53-generic #89-Ubuntu SMP Wed May 20 10:34:39 UTC 2015 x86_64 x86_64 x86_64 GNU/LinuxThe BIOS memory remaping is enabled. I don't know what more to do.
43 Answers
Memory Controller Information
Maximum Memory Module Size: 2048 MB
This part of the output from above would explain what you are seeing. Can you confirm the motherboard used, or check the maximum capacity it will accept for each individual DIMM?
6Sharing my experience: I struggled with this issue all day. In my case, I realized the blue and white slots in my gigabyte motherboard were the issue. Once I put my 4gb ram sticks in the same colored slot(blue) it all worked out :)
Try to match your slots so that the pairs reflects the same speed and manufacturer of the sticks.
Check your CPU speed. Go in the bios and slow it down to accommodate the slowest memory. You might have to test by going slower than the specification to get to a point where the full memory is working.
After you have a working configuration, of course if it works as a results of slowing down the process speed, invest into changing the slowest sticks will faster sticks.
