# RAM SPD editor?

## Slippery Jim

Does anyone know if there exists an app to read and write the SPD EEPROM from a RAM module?

Ideally, I would like to dump the current SPD contents of one of my RAM modules, edit it, and flash it to another module.

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## Chris W

This may be of interest in the kernel configuration: 

```
  │ CONFIG_SENSORS_EEPROM:                                                                             │

  │                                                                                                    │

  │ If you say yes here you get read-only access to the EEPROM data                                    │

  │ available on modern memory DIMMs and Sony Vaio laptops.  Such                                      │

  │ EEPROMs could theoretically be available on other devices as well.                                 │

  │                                                                                                    │

  │ This driver can also be built as a module.  If so, the module                                      │

  │ will be called eeprom.                                                                             │

  │                                                                                                    │

  │ Symbol: SENSORS_EEPROM [=n]                                                                        │

  │ Prompt: EEPROM reader                                                                              │

  │   Defined at drivers/i2c/chips/Kconfig:28                                                          │

  │   Depends on: I2C && EXPERIMENTAL                                                                  │

  │   Location:                                                                                        │

  │     -> Device Drivers                                                                              │

  │       -> I2C support                                                                               │

  │         -> I2C support (I2C [=m])                                                                  │

  │           -> Miscellaneous I2C Chip support                                                        │

```

 I don't know of any way to write to the SPD device (if they are indeed writeable) from Linux.  Seems a dangerous thing since the DIMM may be in use at the time.

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## Slippery Jim

Thanks. I'll play around with that.

I was under the impression that the SPD chip was only queried at boot, by the BIOS, to set the RAM timings. If it is also read during normal operation for other things, then I guess it would be dangerous to mess with it.

I saw a windows program advertised somewhere that claimed to allow users to update the SPD chip, so I assume it's possible.

FWIW, this came up because I got some new PC2700 sticks that my Iwill MPX2 board chokes on. The MPX2 is a 133 MHz FSB DDR board, and I'm running PC2100 on it now. I assumed that the board would run the PC2700 if I manually set the timings and bus speed, but it didn't. It then occurred to me that if I copied the SPD data from a stick of PC2100 to the PC2700 sticks, then it would be all right. I mean, hell, that's what Crucial does with their PC2100 anyway most of the time.

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