# Lost 800MB of RAM

## IvanZD

Hi!

I installed amd64 arch on new hardware (Intel P-35/G33 chipset, Core2Duo 8200, 2x2GB Kingmax RAM in dualchannel mode).

Gentoo reports only 3270MB of RAM:

```
coldplug@ivan ~ $ free -m

             total       used       free     shared    buffers     cached

Mem:          3269        421       2848          0         45        169

-/+ buffers/cache:        206       3062

Swap:         7632          0       7632

```

```
coldplug@ivan ~ $ cat /proc/meminfo

MemTotal:      3348016 kB

MemFree:       2911628 kB

Buffers:         46728 kB

Cached:         173728 kB

SwapCached:          0 kB

Active:         220200 kB

Inactive:       144944 kB

SwapTotal:     7815612 kB

SwapFree:      7815612 kB

Dirty:             192 kB

Writeback:           0 kB

AnonPages:      144836 kB

Mapped:          66432 kB

Slab:            30612 kB

SReclaimable:    14348 kB

SUnreclaim:      16264 kB

PageTables:      11364 kB

NFS_Unstable:        0 kB

Bounce:              0 kB

CommitLimit:   9489620 kB

Committed_AS:   362844 kB

VmallocTotal: 34359738367 kB

VmallocUsed:     43004 kB

VmallocChunk: 34359693819 kB

HugePages_Total:     0

HugePages_Free:      0

HugePages_Rsvd:      0

Hugepagesize:     2048 kB

```

Is that normal? I don't believe that loosing of 800MB RAM is healthy. What do others think? Where could this memory gone?

Thanks.

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## danomac

If you are running 32bit it won't see all 4GB unless you set a 64GB memory limit in the kernel.

```

 Processor type and features  ---> 

    High Memory Support (64GB)  ---> 

```

Windows has this problem as well, although I don't know if you can enable PAE on it. On newer linux kernels (well, gentoo-sources) PAE is not even visible for some reason unless you select the 64GB option.Last edited by danomac on Wed Mar 12, 2008 5:45 pm; edited 1 time in total

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## IvanZD

Thanks for your answer, but.... as I said, it is 64bit architecture (amd64) so this cannot be problem.

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## danomac

Crap, I didn't notice that.   :Embarassed: 

Do you have anything onboard that swipes system memory? Although I can't see it taking 800MB...

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## cyrillic

How much RAM do you have on your video card(s) ?

Can you also post the output of "uname -a" ?

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## IvanZD

Hi, I have nVidia 8600GTS with 256MB RAM.

```
coldplug@ivan ~ $ uname -a

Linux ivan 2.6.23-gentoo-r9 #1 SMP Tue Mar 11 00:12:29 CET 2008 x86_64 Intel(R) Core(TM)2 Duo CPU E8200 @ 2.66GHz GenuineIntel GNU/Linux

```

Thanks for help

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## cyrillic

Hmmm, that is strange.

Maybe there is a "memory hole" option in the BIOS that changes the way the kernel detects RAM.

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## shrimp123

i have the aopen MP965D  with 4GB ram. it also shows 3.3Gb on free.

If i read the MB, it says : MB can accept 4GB ram, but the chipset restrictions will make the only ~3.3gB addressable.

damn marketeers.... now all details are in fine print:(

S

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## ksp7498

even on amd64, you need a motherboard that supports memory remapping in order to use all 4gb of ram.  All Athlon 64 cpus support it because the memory controller is on the cpu die, but for intel platforms it depends entirely on the motherboard chipset.

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## eccerr0r

My Intel G965 chipset appears to remap fine as well.  4GB RAM gets seen even in PAE/32-bit mode.

I suppose newer chipsets should have no problem remapping, might also want to check for firmware upgrades.

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## IvanZD

 *eccerr0r wrote:*   

> My Intel G965 chipset appears to remap fine as well.  4GB RAM gets seen even in PAE/32-bit mode.
> 
> I suppose newer chipsets should have no problem remapping, might also want to check for firmware upgrades.

 

 *cyrillic wrote:*   

> Hmmm, that is strange.
> 
> Maybe there is a "memory hole" option in the BIOS that changes the way the kernel detects RAM.

 

Thanks guys, catch were in BIOS settings, "Allow memory remapping" was "Disabled"! Now works like a charm!

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## shrimp123

darn it. my m/c's bios has no such option  :Sad: 

it has like a waste of 6 options. and no mem-remap.

S

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