How do you check RAM voltage from Linux (can't see that on BIOS)

Solution 1:

I've used dmidecode.

dmidecode -t [type] (use 5 for voltage and 17 for memory details.)

ie. dmidecode -t 5

Type List

 0   BIOS
 1   System
 2   Base Board
 3   Chassis
 4   Processor

---

 5   Memory Controller

---

 6   Memory Module
 7   Cache
 8   Port Connector
 9   System Slots
10   On Board Devices
11   OEM Strings
12   System Configuration Options
13   BIOS Language
14   Group Associations
15   System Event Log
16   Physical Memory Array

---

17   Memory Device

---

18   32-bit Memory Error
19   Memory Array Mapped Address
20   Memory Device Mapped Address
21   Built-in Pointing Device
22   Portable Battery
23   System Reset
24   Hardware Security
25   System Power Controls
26   Voltage Probe
27   Cooling Device
28   Temperature Probe
29   Electrical Current Probe
30   Out-of-band Remote Access
31   Boot Integrity Services
32   System Boot
33   64-bit Memory Error
34   Management Device
35   Management Device Component
36   Management Device Threshold Data
37   Memory Channel
38   IPMI Device
39   Power Supply

Man dmidecode

Some content was taken from here.

P.S : It works with MoBo with DMI zone

Solution 2:

Use dmidecode with type 17

sudo dmidecode --type 17

Output

# dmidecode 3.1
Getting SMBIOS data from sysfs.
SMBIOS 2.7 present.

Handle 0x0018, DMI type 17, 40 bytes
Memory Device
    Array Handle: 0x0005
    Error Information Handle: Not Provided
    Total Width: Unknown
    Data Width: Unknown
    Size: No Module Installed
    Form Factor: Other
    Set: None
    Locator: Bottom-Slot 1(top)
    Bank Locator: ChannelA
    Type: Unknown
    Type Detail: None
    Speed: Unknown
    Manufacturer: Not Specified
    Serial Number: Not Specified
    Asset Tag: Not Specified
    Part Number: Not Specified
    Rank: Unknown
    Configured Clock Speed: Unknown
    Minimum Voltage: Unknown
    Maximum Voltage: Unknown
    Configured Voltage: Unknown

Handle 0x0006, DMI type 17, 40 bytes
Memory Device
    Array Handle: 0x0005
    Error Information Handle: Not Provided
    Total Width: 64 bits
    Data Width: 64 bits
    Size: 4096 MB
    Form Factor: SODIMM
    Set: None
    Locator: Bottom-Slot 2(under)
    Bank Locator: ChannelB
    Type: DDR3
    Type Detail: Synchronous Unbuffered (Unregistered)
    Speed: 1600 MT/s
    Manufacturer: Ramaxel
    Serial Number: 436BC413
    Asset Tag: 9876543210
    Part Number: RMT3170MN68F9F1600
    Rank: 1
    Configured Clock Speed: 1600 MT/s
    Minimum Voltage: Unknown
    Maximum Voltage: Unknown
    Configured Voltage: 1.35 V

See bottom of the output, ram voltage is specified there. I have two ram slots, I am using only the second one and configured voltage for that slot is:

Configured Voltage: 1.35 V