How to Use more than 3GB RAM on 32-bit Ubuntu
Posted by admin on September 23rd, 2008 
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Currently It seems that the current 32 bit editions of Ubuntu can only take advantage of 3GB (sometimes a little more) of physical memory. Desktops and gaming rigs using 6 and 8 GB of RAM are ubiquitous now.I am having a ubuntu desktop with 5GB RAM and i want to use all the available memory for gaming.
Procedure to follow
You need to install the following packages and restart your PC
sudo apt-get install linux-restricted-modules-server
sudo apt-get install linux-headers-server
sudo apt-get install linux-image-server linux-server
That’s it after rebooting you should be able to see all the memory available in your system.
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September 23rd, 2008 at 6:35 pm
does this work, I thought 32 bit os can only use 2GB of ram for user.
September 23rd, 2008 at 6:54 pm
You want to use your system for gaming - and you install a kernel made for non-interactivity - the server flavor..
Sounds like a bad choice if you ask me..
Better way to do it would be to grab the sources and config for the desktop kernel, add PAE support yourself, build a package.. Done in a couple of commands.. or just go for the 64 bit version..
.. oh, and you should probably also explain a bit about PAE-mode and so on, not just write “install server kernel”..
September 23rd, 2008 at 7:29 pm
Can you explain how this is even possible? The addressable limit on a 32-bit processor is 2^32 => 4 GB. Thus, it seems there should be a hard-cap at 4GB. 32-bit Windows actually gets a little less than this, because additional address space is reserved for other hardware I/O.
How does this separate kernel (I assume that’s the difference) provide addressing over this cap?
September 23rd, 2008 at 8:02 pm
Should I expect any problem after installing those packages ?
Will I be able to remove them in case It will not work out properly ?
September 23rd, 2008 at 8:05 pm
@scott
Linux cannot use more than 3 GB RAM per process on a 32 bit machine (using the default CONFIG_VMSPLIT_3G=y).
But if your CPU supports PAE (http://en.wikipedia.org/wiki/Physical_Address_Extension) - which is very likely - you can use more than 3 GB RAM for the whole system.
September 23rd, 2008 at 8:10 pm
Hello,
Just one question. Why not directly deploy 64bit system instead of using server kernel?
What are advantages or disadvantages?
Alecs
September 23rd, 2008 at 9:43 pm
@Admin: Thanks for the link on PAE, I had never heard of it before. Who knew x86 had an extra 4 bits, cool!
@Alecs: The benefits is that you can still take advantage of your extra RAM if you’re stuck on a 32-bit CPU. If you have a 64-bit machine, by all means, go for a 64-bit version of the OS.
September 23rd, 2008 at 11:54 pm
The advantage of 32bit is compatibility.. some things such as Flash and Quake4 are 32bit only (proprietary things usually, opensouce is fine)
I run 64bit because I have 8gb and yes flash does work with a wrapper but every now and then you have to close the browser because videos just freeze up. Very frustrating if you have loads of tabs open.
Adobe are so slow to develop by the time is is sorted HTML5 will have native video (h.264) and we won’t even need it lol
September 25th, 2008 at 5:34 am
I use 64 Bit Hardy and I haven’t had any compatibility issues at all. Many programs such as Skype require a 32 Bit machine to work properly but with 64 Bit Ubuntu you can force the application to work, and it works perfectly. As far is Flash applicatons are concerned I haven’t had any adverse issues regarding it’s use. For my laptop I have a 1.66 Ghz Intel Core 2 Duo with 2 Gigs of RAM.
So my suggestion is that if you have a 64 Bit processor then by all means use the 64 Bit OS.
September 25th, 2008 at 7:24 am
Hi there,
You said that “the current 32 bit editions of Ubuntu can only take advantage of 3GB (sometimes a little more) of physical memory.” Then my question is, how can we know that?
I want to see the differences before install those packages and after install those packages you mentioned.
Thanks for your answer
Tje
September 25th, 2008 at 2:59 pm
@Tje: I think you can, after installing the packages, run free, htop or top and you’ll see that you’re using say 5 of the 8 gigs of RAM that you have, then in this case you are accessing more than 3G of mem.
If you don’t like then you can easily remove the packages and restore the old kernel or you can even keep both and try each for a while
September 25th, 2008 at 11:05 pm
cool i just Googlebookmarked this one
September 26th, 2008 at 8:20 am
Hi Diaa,
Yes you are right, we can check right away using free or top tools. I should think of these tools before asking. I know already these tools, just didn’t think of it before.
Thanks mate.
September 26th, 2008 at 9:19 am
Hi there,
Another curious question, I see that the packages we need to install are related to server, not for gaming, not even related to memory or swap. How come those packages could affect memory management?
Thanks for the response
September 26th, 2008 at 11:37 am
@Tje
Please read the link menctioned in comment#5 you will get better understanding of linux 32-bit kernel
October 2nd, 2008 at 7:08 pm
I have a laptop with 4 gb RAM, but the Ubuntu 8.04 64 bit just recognizes 2,9 gb RAM. I tried to install a server kernel, but it did not work. I can’t understand why…
October 4th, 2008 at 7:58 pm
@Antares
Most likely because the motherboard chips don’t support an address space that large. I use a MacBook Pro, and until the Santa Rosa chips started to be used, I could get to the 4GB of RAM that the system can hold. I could take the same chips and put them into the Santa Rosa-based MacBook Pro my daughter has, and yep, all 4 GB are accessible.
Looks like this may be a hardware limitation on your side.
October 15th, 2008 at 12:37 pm
Well installing these packages surely made ubuntu recognize my last 1GB of RAM. However they also uninstalled my wireless netcard driver…
October 25th, 2008 at 9:32 pm
Thanks!
Un millón de gracias! Funciona perfecto!!
November 20th, 2008 at 3:20 am
to clean install for linux server kernel usi this command:
sudo apt-get install linux-restricted-modules-server linux-headers-server linux-image-server linux-server avm-fritz-firmware drdsl
** after install lation reboot. you can login normal as usual
November 20th, 2008 at 3:24 am
after login you can easily see you are using all 4gb RAM in Sysinfo