On 1/3/23 06:04, Eivind Nicolay Evensen wrote:
Hello.
This might be more related to a bios setting or issue, but I hope
somebody can give me hints in the right direction to remedy or
at least diagnose this issue further.
I installed more memory in one machine and now I see this
in dmesg:
real memory = 25769803776 (24576 MB)
avail memory = 8237150208 (7855 MB)
Real should be right, from before there were two 4 GB dimms in there,
and I inserted two more 8 GB ones.
Transcribed from BIOS:
DIMM(s) 1 2 3 4
Installed Size 8192 8192 4096 4096
Enabled Size 8192 8192 4096 4096
Total Size 24576
I was wondering if the reason could be that this machine has been updated
since older versions and bootloader may be old or whatever, so I also tried
booting a linux. However, that also only uses 8 GB, and says (at least in a
way I understand) less about what it can really see.
This is amd64 FreeBSD 13.1.
Is there any way I can use the rest of the memory? Or at least find out
which dimms it is actually using?
I agree. A BIOS update may also impact on what memory is supported
too. It is usually for the better bot not always.
Some memory uses fewer but more dense chips while others use more but
less dense memory chips and which is supported can vary. Sometimes a
memory manufacturer revises a stick and it may alter its compatibility
too. You can also attempt to remove 1 to 3 sticks to see how it is
handling the 8GB modules. They may have incompatible specifications
where the system may stop booting if you do not have a 4GB stick in or
even depending which slot it is in. If something is only a little out of
tolerance then you may be able to try different sticks in different
slots to bring them online.
I usually recommend checking memory manufacturers for what they will
claim they tested their memory modules with instead of the motherboard
manufacturer as motherboard manufacturers do not test all sticks out
there (=unnecessarily small compatibility list) and do not usually
update their compatibility chart as BIOS updates and different CPU's
built in memory controllers impact it.
If you lookup specs for your related memory controller, you may find
it has a limited amount of RAM supported. It is doubtful, though not
impossible, that a BIOS update will bypass such a limitation. For Intel
processors I usually just do a google search for ark + processor model
to see max supported memory. intel.com ark pages are where you find
processor specifications in an easy layout for their chips. Wish I knew
of comparable lookups for AMD, ARM, etc.
