# High memory support

## microchiroptera

I've installed Gentoo few days ago and noticed that it doesn't recognize all of my RAM (I have 2048 MB and it recognized only about 880 MB). I googled it and found that I must enable high memory support in my kernel (2.6.38-r6). I enabled it and reemerged nvidia-drivers, but after it I have errors: Xorg doesn't start because of nVidia (it says "Failed to load the NVIDIA kernel module") and modprobe nvidia doesn't work: it says "FATAL: Error Inserting nvidia: Invalid module format". I disabled high memory support, and now everything is ok except RAM. What can I do to fix it? And sorry for my english  :Smile: 

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## NeddySeagoon

microchiroptera,

Welcome to Gentoo.

Your English appears to be very good, so no worries there.

Changing high memory support in the kernel is one of the few things where you mist recompile the entire kernel and all the modules that build against the kernel.

If your kernel has been compiled before, make will look at the timestamps on the existing .o files and the .c and .h files that are used to make the .o  

If the .o file is newer, make will think that thee is nothing to do and use the existing .o file, which is missing the high memory support.

Choose High Memory Support in the kernel.

Run the command 

```
make clean
```

to remove all of the old .o files

Now when you make your kernel, it will make everything correctly.

Install your kernel normally but don't reboot yet.

```
emerge -1 nvidia-drivers
```

 will rebuild the nvidia drivers against the new kernel.

When you reboot, it should all just work.

You will also have to rebuild any other out of kernel kernel modules, if you have any.

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## microchiroptera

Thank you for your answer!

 *NeddySeagoon wrote:*   

> 
> 
> Choose High Memory Support in the kernel.
> 
> Run the command 
> ...

 

I used genkernel, so can I use it now with --clean flag? Or it isn't the same?

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