RAM MTRR problem

[gaffu]

Hi,

I have added 2GM of RAM to my machine, now I have 4 GB (on a 64bit machine so no problem with memory adressing).

The problem is that I can see "only" 4060496 kB (value found using top), which means ~3965 MB (~3.87 GB).

I think I have a problem whit MTRR:

Code: Select all

$ cat /proc/mtrr
reg00: base=0x00000000 (   0MB), size=2048MB: write-back, count=1
reg01: base=0x80000000 (2048MB), size=1024MB: write-back, count=1
reg02: base=0xc0000000 (3072MB), size= 512MB: write-back, count=1
reg03: base=0xdff00000 (3583MB), size=   1MB: uncachable, count=1
reg04: base=0x100000000 (4096MB), size= 512MB: write-back, count=1


Note the line reg03: uncachable

I have found some information here http://www.gentoo.org/doc/en/nvidia-guide.xml#doc_chap4, it is said that to resolve the issue one has to change the MTRR setting in the BIOS from continuous to discrete BUT I can't see such a setting in my BIOS (ASUS M2N Sli deluxe). Actually I don't think that this setting is controlled by the BIOS in K8 processors...

Anyone has an idea?

Thanks

[Dark_MaGe]

it's a correct value, do you have problem loading nvidia drivers???? if not why caring about that? mtrr registers are fixed by the motherboard/cpu registers, remember also that you might have a memory hole actived on the bios check that

[gaffu]

it's a correct value, do you have problem loading nvidia drivers????

No, it's working perfectly.

if not why caring about that? mtrr registers are fixed by the motherboard/cpu registers, remember also that you might have a memory hole actived on the bios check that

I just want to use all of my RAM, I do numerical simuations sometimes on this PC and I need this amount of RAM when running big cases.
What do you mean by memory hole on the BIOS?

Anyway, thank you for your answer Dark Mage, if I understand you correctly my MTRR has no problem, that's good news...

[Dark_MaGe]

sorry I remembered the wrong option, it's not the memory hole it's the 4 Gb remapping, but in any case reading around it's a matter of arrangement of memory so your memory is mapped that way and you're already using all the ram you have

[gaffu]

Ok, thanks again for the really quick reply. I will look into that tonight, but I can't remember such an option in my BIOS. Maybe flushing it will help.
When/if I make some progress I will report them here, in case somone else is concerned.