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Jestep
Asked: 2010-05-01 10:22:16 +0800 CST

dmidecode showing more ram slots than available?

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I have some failing RAM in a server and I ran dmidecode to figure out what tyoe of RAM I needed to replace it with.

The server has 6 RAM slots, 4 of which are in use. When I run dmidecode this is what I get.

dmidecode 2.10
SMBIOS 2.4 present.

Handle 0x001F, DMI type 17, 27 bytes
Memory Device
        Array Handle: 0x001E
        Error Information Handle: No Error
        Total Width: 72 bits
        Data Width: 64 bits
        Size: 2048 MB
        Form Factor: DIMM
        Set: 1
        Locator: JXXX
        Bank Locator: DIMM 00
        Type: DDR2
        Type Detail: Synchronous
        Speed: 667 MHz
        Manufacturer: Not Specified
        Serial Number: Not Specified
        Asset Tag: Not Specified
        Part Number: Not Specified

Handle 0x0020, DMI type 17, 27 bytes
Memory Device
        Array Handle: 0x001E
        Error Information Handle: No Error
        Total Width: 72 bits
        Data Width: 64 bits
        Size: 2048 MB
        Form Factor: DIMM
        Set: 1
        Locator: JXXX
        Bank Locator: DIMM 01
        Type: DDR2
        Type Detail: Synchronous
        Speed: 667 MHz
        Manufacturer: Not Specified
        Serial Number: Not Specified
        Asset Tag: Not Specified
        Part Number: Not Specified

Handle 0x0021, DMI type 17, 27 bytes
Memory Device
        Array Handle: 0x001E
        Error Information Handle: No Error
        Total Width: Unknown
        Data Width: Unknown
        Size: No Module Installed
        Form Factor: DIMM
        Set: 1
        Locator: JXXX
        Bank Locator: DIMM 02
        Type: DDR2
        Type Detail: Synchronous
        Speed: 667 MHz
        Manufacturer: Not Specified
        Serial Number: Not Specified
        Asset Tag: Not Specified
        Part Number: Not Specified

Handle 0x0022, DMI type 17, 27 bytes
Memory Device
        Array Handle: 0x001E
        Error Information Handle: No Error
        Total Width: Unknown
        Data Width: Unknown
        Size: No Module Installed
        Form Factor: DIMM
        Set: 1
        Locator: JXXX
        Bank Locator: DIMM 03
        Type: DDR2
        Type Detail: Synchronous
        Speed: 667 MHz
        Manufacturer: Not Specified
        Serial Number: Not Specified
        Asset Tag: Not Specified
        Part Number: Not Specified

Handle 0x0023, DMI type 17, 27 bytes
Memory Device
        Array Handle: 0x001E
        Error Information Handle: No Error
        Total Width: 72 bits
        Data Width: 64 bits
        Size: 2048 MB
        Form Factor: DIMM
        Set: 1
        Locator: JXXX
        Bank Locator: DIMM 10
        Type: DDR2
        Type Detail: Synchronous
        Speed: 667 MHz
        Manufacturer: Not Specified
        Serial Number: Not Specified
        Asset Tag: Not Specified
        Part Number: Not Specified

Handle 0x0024, DMI type 17, 27 bytes
Memory Device
        Array Handle: 0x001E
        Error Information Handle: No Error
        Total Width: 72 bits
        Data Width: 64 bits
        Size: 2048 MB
        Form Factor: DIMM
        Set: 1
        Locator: JXXX
        Bank Locator: DIMM 11
        Type: DDR2
        Type Detail: Synchronous
        Speed: 667 MHz
        Manufacturer: Not Specified
        Serial Number: Not Specified
        Asset Tag: Not Specified
        Part Number: Not Specified

Handle 0x0025, DMI type 17, 27 bytes
Memory Device
        Array Handle: 0x001E
        Error Information Handle: No Error
        Total Width: Unknown
        Data Width: Unknown
        Size: No Module Installed
        Form Factor: DIMM
        Set: 1
        Locator: JXXX
        Bank Locator: DIMM 12
        Type: DDR2
        Type Detail: Synchronous
        Speed: 667 MHz
        Manufacturer: Not Specified
        Serial Number: Not Specified
        Asset Tag: Not Specified
        Part Number: Not Specified

Handle 0x0026, DMI type 17, 27 bytes
Memory Device
        Array Handle: 0x001E
        Error Information Handle: No Error
        Total Width: Unknown
        Data Width: Unknown
        Size: No Module Installed
        Form Factor: DIMM
        Set: 1
        Locator: JXXX
        Bank Locator: DIMM 13
        Type: DDR2
        Type Detail: Synchronous
        Speed: 667 MHz
        Manufacturer: Not Specified
        Serial Number: Not Specified
        Asset Tag: Not Specified
        Part Number: Not Specified

Does anyone know why it would show 8 slots, with 4 empty instead of 6 slots with 2 empty? Also, but my records and by other tools, the server has 16Gb and not 8Gb in it currently. 

grep MemTotal /proc/meminfo
MemTotal:     16435808 kB

The board is a Tyan S5372-LC, running CentOS 5.4 x64.

Also, my error log is showing errors in bank 6. Is there any way to determine which slot bank 6 is in via: dmidecode?

Sorry, I can't comment as of now, but the message with the bank 6 error is:

EDAC MC0: CE row 0, channel 0, label "": (Branch=0 DRAM-Bank=6 RDWR=Read RAS=1755 CAS=2492, CE Err=0x2000 (Correctable Non-Mirrored Demand Data ECC))
centos memory

1 Answers

  1. Best Answer

    The chipset supports 8 memory slots. There's likely plumbing for 8 actual DIMM slots, but only 6 of them are connected. The motherboard manufacturer could have put 8 slots onto the board, but chose not to.

    What's saying there's an error in "Bank 6"? Some kind of server management console? One of the slots is probably labelled as DIMM06 on the motherboard - I'd check that.

    As for the size discrepancy, it's likely that you actually do have 4GB DIMMs installed, but a bug in your BIOS or DMI table is reporting them as only 2GB DIMMs.

    Bottom line: don't trust dmidecode, it's not giving you enough information here. Visual inspection is required.

    (or alternatively, check Tyan's website)

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