2016년 3월 19일 토요일

ASUS U36JC Notebook Intel H55 chipset does not support 8GB DDR3 modules

I have happily used a 13.3" ASUS U36JC notebook since 2011. When I bought it I made sure that 8GB DDR3 of total memory was installed (2 x 4GB DDR3). Back then, 8GB was a large amount of memory, but as the years have gone by, I have required more and more memory (Chrome has become a memory hog, and I use virtualization via KVM and virtualbox much more frequently).

Recently at work I have been put on an Openstack project so I want to be able to play with Openstack at home on my personal notebook as well. Although simple all-in-one(AIO) installations will work with just 8GB of RAM, standalone physical installations using the Ubuntu installer for Openstack Kilo require at least 12GB, while installation of the Kolla project (which containerizes all Openstack components within Docker) requires > 8GB to build and run ~80 containers.

I used dmidecode to query the system BIOS for max memory supported and info on the memory modules currently populating the memory banks.

[fedjun@u36jfed23 ~]$ sudo dmidecode -t 16
# dmidecode 3.0
Getting SMBIOS data from sysfs.
SMBIOS 2.6 present.

Handle 0x0041, 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


DMI type 16 shows the Physical Memory Array. According to the information above, the motherboard has 4 memory slots and can support a total of 16GB of RAM. This means that each memory bank can support up to 4GB RAM. Note that although the Intel H55 chipset can support up to 4 physical memory banks, there are only two physical memory slots offered on the ASUS U36JC. According to the following Superuser forum thread, this is not an unusual occurrence:

http://serverfault.com/questions/137491/dmidecode-showing-more-ram-slots-than-available

But since the mobo can theoretically support up to 16GB DDR3, I decided to make a gamble and purchased two Samsung Electronics 8GB DDR3L PC-12800 memory modules:


The picture above shows the 8GB DDR3L (low-power 1.35V) memory modules installed on my ASUS U36JC notebook. Here is the information on the memory modules provided by dmidecode reading from the BIOS:

[fedjun@u36jfed23 ~]$ sudo dmidecode -t 17
[sudo] password for fedjun:
# dmidecode 3.0
Getting SMBIOS data from sysfs.
SMBIOS 2.6 present.

Handle 0x0042, DMI type 17, 28 bytes
Memory Device
    Array Handle: 0x0041
    Error Information Handle: Not Provided
    Total Width: 64 bits
    Data Width: 64 bits
    Size: 8192 MB
    Form Factor: SODIMM
    Set: None
    Locator: DIMM0
    Bank Locator: BANK 0
    Type: DDR3
    Type Detail: Synchronous
    Speed: 1067 MHz
    Manufacturer: 80CE
    Serial Number: 312BBD50
    Asset Tag: Unknown
    Part Number: M471B1G73DB0-YK0 
    Rank: Unknown

Handle 0x0044, DMI type 17, 28 bytes
Memory Device
    Array Handle: 0x0041
    Error Information Handle: Not Provided
    Total Width: Unknown
    Data Width: Unknown
    Size: No Module Installed
    Form Factor: DIMM
    Set: None
    Locator: DIMM1
    Bank Locator: BANK 1
    Type: Unknown
    Type Detail: None
    Speed: Unknown
    Manufacturer: [Empty]
    Serial Number: [Empty]
    Asset Tag: Unknown
    Part Number: [Empty]
    Rank: Unknown

Handle 0x0045, DMI type 17, 28 bytes
Memory Device
    Array Handle: 0x0041
    Error Information Handle: Not Provided
    Total Width: 64 bits
    Data Width: 64 bits
    Size: 8192 MB
    Form Factor: SODIMM
    Set: None
    Locator: DIMM2
    Bank Locator: BANK 2
    Type: DDR3
    Type Detail: Synchronous
    Speed: 1067 MHz
    Manufacturer: 80CE
    Serial Number: 312BBD72
    Asset Tag: Unknown
    Part Number: M471B1G73DB0-YK0 
    Rank: Unknown

Handle 0x004A, DMI type 17, 28 bytes
Memory Device
    Array Handle: 0x0041
    Error Information Handle: Not Provided
    Total Width: Unknown
    Data Width: Unknown
    Size: No Module Installed
    Form Factor: DIMM
    Set: None
    Locator: DIMM3
    Bank Locator: BANK 3
    Type: Unknown
    Type Detail: None
    Speed: Unknown
    Manufacturer: [Empty]
    Serial Number: [Empty]
    Asset Tag: Unknown
    Part Number: [Empty]
    Rank: Unknown


DMI type 17 shows the Memory Device. Banks 0 and 2 are populated and Banks 1 and 3 are empty (and do not physically exist on the U36JC Intel H55 chipset motherboard).

BIOS detects the memory modules and Linux will boot; however, once a memory address above 4GB is accessed, the system will reboot or a kernel panic will result. I contacted ASUS and asked if a BIOS upgrade could fix this issue, but ASUS tech support responded that this is a physical limitation of the H55 chipset as implemented on the mobo for the ASUS U36JC.

It seems that the maximum amount of memory supported in each memory bank is 4GB!