3.5G Memory limit on MSI K8N Athlon 64 Boards

[General Schvantzkoph]

This morning I reported that the MSI K8N Neo4 Platinum can only recognize
3.5G of memory. The MSI website says,

Due to the South Bridge resource deployment, the system density will only
be detected up to 3+ GB (not full 4GB) when each DIMM is installed with an
1GB memory module

I also have an MSI K8N Neo2 Platinum. I just tried putting 4G into the the
Neo2 to see if it has the same defect, it does. So it appears that all MSI
Nforce 3 and Nforce 4 boards are limited to 3.5G.

Does anyone have a Athlon 64 motherboard that supports the full 4G?

 

[kermit]

This morning I reported that the MSI K8N Neo4 Platinum can only recognize
3.5G of memory. The MSI website says,

Due to the South Bridge resource deployment, the system density will only
be detected up to 3+ GB (not full 4GB) when each DIMM is installed with an
1GB memory module

I also have an MSI K8N Neo2 Platinum. I just tried putting 4G into the the
Neo2 to see if it has the same defect, it does. So it appears that all MSI
Nforce 3 and Nforce 4 boards are limited to 3.5G.

Does anyone have a Athlon 64 motherboard that supports the full 4G?

I believe similar question has been asked recently. PCI resources should be
under 4GB so BIOS reserves part of address space for them. Check your BIOS
for option like "Remap PCI gap" or similar. In this case physical memory in
this range will be remapped above 4GB.

=arvi=

 

[General Schvantzkoph]

I believe similar question has been asked recently. PCI resources should be
under 4GB so BIOS reserves part of address space for them. Check your BIOS
for option like "Remap PCI gap" or similar. In this case physical memory in
this range will be remapped above 4GB.

=arvi=

The remap memory hole is incompatible with Linux. I've tried a number of
kernels including 2.6.13.rc3, when the remapping option is selected Linux
only sees 3G.

 

[Doug Lynn]

Hi, no thats true for all chipsets I believe I usually see about 3.6-3.8G
tho.

doug
www.lynncomp.com

 

[Henrik Carlqvist]

Hi, no thats true for all chipsets I believe I usually see about 3.6-3.8G
tho.

At work I have a Dual Opteron machine with AMD chipset (Iwill
motherboard), that machine has the same behavior, it only sees about 3.5
GB. However, I'm running a 32-bit Linux where the kernel is configured
with CONFIG_HIGHMEM4G=y which limits it to support only upp to 4 GB of
memory. Maybe I would be able to see all RAM if I had CONFIG_HIGHMEM64G=y
or if I had a 64 bit kernel.

I also have a dual Xeon machine at work with 4 GB (Tyan motherboard, I
don't remember which chipset). That machine is able to use all 4 GB.

regards Henrik

 

[General Schvantzkoph]

At work I have a Dual Opteron machine with AMD chipset (Iwill
motherboard), that machine has the same behavior, it only sees about 3.5
GB. However, I'm running a 32-bit Linux where the kernel is configured
with CONFIG_HIGHMEM4G=y which limits it to support only upp to 4 GB of
memory. Maybe I would be able to see all RAM if I had CONFIG_HIGHMEM64G=y
or if I had a 64 bit kernel.

I also have a dual Xeon machine at work with 4 GB (Tyan motherboard, I
don't remember which chipset). That machine is able to use all 4 GB.

regards Henrik

I've tried 64G highmem as well as a 64 bit kernel. Another poster with an
ABIT board says that it's BIOS reports the full 4G both with and without
the fill memory hole option being selected. The MSI board only reports 4G
with the fill memory hole option on. However Linux seems to be confused by
that option. If there is a mem=4G in the grub boot line it will boot but
only see 3G. If the mem= line isn't there it won't boot.