# 1Gb of Ram not showing as 1Gb of ram.

## lotas

My system has 2 512Mb DDR Dimms and on boot it shows 1Gb of ram. but gentoo shows 882Mb. 

```

lotas@batman lotas $ free -m

             total       used       free     shared    buffers     cached

Mem:           882        763        118          0        156        449

-/+ buffers/cache:        158        724

Swap:          980         25        955

lotas@batman lotas $

```

.

Any ideas on how to fix this? is there actually a problem? by my calculations, 882mb is 924844032 bytes, which is 924mibytes (i think). (882*1024*1024/1000/1000). Is there a problem somewhere? i have an MSI K7D and Athlon 1.33Gz processor. no im not mad. im getting my 2 CPUs for it soon. Its not a major problem, but i would like to find out whats up with it.

Thanks.

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## zhenlin

There was a problem with the NVIDIA kernel module which caused about 384MB of address space to disappear, I think. In your situation, 142MB is missing.

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## lotas

i dont have the NVida kernel. its 2.4.21 vannilla. i added a bluetooth patch, but thats it.

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## paranode

You have to enable high memory support in the kernel.  It's under processor support stuff.

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## lotas

though that was only for 4gb or 64gb. Ok. ill try it. the 4Gb should be enough, right?!  :Razz: 

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## Vxster

Yup, 4GB should be enough...it is for any machine with > 960 Mb RAM and so yours falls into that category. I was also getting reporting of less than 1 Gb on my servers before I changed this option.

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## lotas

Right. ill try that soon. Thanks for your replys!!!

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## lloyd

I ran into this exact same problem.

I installed an extra 512MB of ram, bringing my total up to 1GB. When I rebooted dmesg told me that linux could not address all of my memory and that I should enable HI Memory support for my kernel.  I rebuilt my kernel with 4GB High memory support and turned on HIGHMEM I/O. My new kernel booted without error. However, now I cannot run X. My XFree86.0.log complains about overlapping memory regions. Does any one have any suggestions?

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## zhenlin

Turn on "Medium" memory support, 2GB or 3GB; not 3.5GB or 4GB

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## paranode

 *lloyd wrote:*   

> I ran into this exact same problem.
> 
> I installed an extra 512MB of ram, bringing my total up to 1GB. When I rebooted dmesg told me that linux could not address all of my memory and that I should enable HI Memory support for my kernel.  I rebuilt my kernel with 4GB High memory support and turned on HIGHMEM I/O. My new kernel booted without error. However, now I cannot run X. My XFree86.0.log complains about overlapping memory regions. Does any one have any suggestions?

 

Do you have MTRR support compiled in? (Memory Type Range Registers I think, also in Processor menu).

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## lloyd

Turn on "Medium" memory support, 2GB or 3GB; not 3.5GB or 4GB  :Question: 

I don't think thats a kernel option. I can only see

  CONFIG_NOHIGHMEM

  CONFIG_HIGHMEM4G

  CONFIG_HIGHMEM64G

Yes I do have MTRR support compiled in.

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## lloyd

I did some more searching and I found this reference

http://www.myri.com/scs/READMES/README-linux

I will try it tonight.

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## zhenlin

Oops, I mean address space, but I see that enabling high memory was the correct option.

I don't know what the default address space size is, but it is probably 2GB, which is probably not enough for X.

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## trossachs

I've also enabled High Memory (4G), but I still only see around 900MB of my installed 2GB. Any other ideas?

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## albright

 *Quote:*   

> I've also enabled High Memory (4G), but I still only see around 900MB of my installed 2GB. Any other ideas?

 

Have you tried passing the correct amount memory to the

kernel in the grub.conf file (something like "mem =2048M"

maybe)?

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## trossachs

Sorted out by reinstalling with 2.6.23.

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