While I too believe that it is a BIOS setting that is giving you troubles,
as another suggestion and data point, whenever I install new memory,
I run memtest (via the install CD boot: prompt) and let memory tests
run overnight [if it finds all the memory installed on the box.]. If it
doesn't find all the memory, you want to start looking at the memory sticks,
are they seated correctly, etc. Finally, I check timing.
Then, if Linux doesn't see the memory, it is usually the BIOS that
is the problem (at least for me where my memory is less than 8 GB).
Also, I go over the first couple of pages of dmesg (at boot-up) with a
fine tooth comb and understand all the messages, their implications, etc.
If all else fails, I use the* Linux*-ready *Firmware* Developer Kit at:
http://www.linuxfirmwarekit.org/
While it doesn't do a lot with memory, it might find some "issues" with
your BIOS .....
Hope this helps ...
Rich
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