System only sees 8 of 16 GB of RAM

Richard Esplin richard-lists at esplins.org
Tue Aug 3 22:07:31 MDT 2010


I am curious if anyone has any insight into my problem.

My new ThinkPad W510 arrived today. Though it is a nice machine, I am very annoyed that Lenovo stopped selling machines with Linux preinstalled. But that is a complaint for another day.

I ordered the minimum RAM from Lenovo, and then ordered 16 GB (4 x 4 GB sodimms) off of NewEgg. I replaced the memory, and rebooted the machine.

Facts:

* The BIOS only reports 8GB of installed memory.
* Using "free", Linux appears to only see 7GB of memory--I am guessing the video card has the rest.
* Memtest reports only 3GB of memory, but I think this is a known bug.
* Memtest reports 4x4GB Dimms installed. It correctly lists the brand and model of each sodimm.
* Lenovo advertises this model as supporting 16 GB in 4 sodimms.
* I'm using Kubuntu 10.04 x64.
* I checked my BIOS version and it appears to be the lastest (1.24).

Questions:

* How can memtest see the sodimms, but the OS isn't using them?
* Do I need to do something for all the RAM to appear?
* If one sodimm is bad, will it prevent the other one from being used? (i.e. do they have to be paired?)
* Any suggestions on what I should do next?

Thank you,

Richard


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