4GB RAM displays as 3GB

pickarooney

I've made a new build with 2 x 2GB sticks of DDR3 RAM. In system monitor the total available RAM is showing up as 3GB.

Is there some reliable way of checking if system-monitor is showing the right figures or should I take out one stick then the other to see the individual sizes?

EDIT: OK, I should really have googled this before I bought 4GB of RAM for a 32-bit OS

Rockn

Yeah there's a PAE kernel that allows you to use all your RAM with 32 bit OS. Which distro are you using?

pickarooney

Ubuntu Maverick. I'll have a look at that but first I have two urgent issues with the new box!

dubhthach

pickarooney wrote: »

I've made a new build with 2 x 2GB sticks of DDR3 RAM. In system monitor the total available RAM is showing up as 3GB.

Is there some reliable way of checking if system-monitor is showing the right figures or should I take out one stick then the other to see the individual sizes?

EDIT: OK, I should really have googled this before I bought 4GB of RAM for a 32-bit OS

If the system is using DDR3 surely it can support a 64bit OS, what gives?

niallb

No need to open the box, this will show you what sticks are installed:
sudo lshw -c memory

You don't need to install a 64 bit OS just because the hardware can run it.
Of course it will support it, but there are still some compatibilty issues if you run 64 bit,
and 32 bit is easier for now. If you've a good reason to need a full 64 bit OS, you'll already know.

If you're running Maverick, this in a terminal and a reboot will sort you out:

sudo apt-get install apt-get install linux-generic-pae linux-headers-generic-pae

(If you're running any kernel modules that need to be rebuilt by dkms,
headers-generic-pae package will allow them to be rebuilt when you reboot.)

Khannie

Rockn wrote: »

Yeah there's a PAE kernel that allows you to use all your RAM with 32 bit OS. Which distro are you using?

Is there not a performance hit for that? I remember with the "bigmem" kernels there was.

niallb wrote: »

No need to open the box, this will show you what sticks are installed:
sudo lshw -c memory

Nice!

niallb wrote: »

You don't need to install a 64 bit OS just because the hardware can run it.
Of course it will support it, but there are still some compatibilty issues if you run 64 bit,
and 32 bit is easier for now. If you've a good reason to need a full 64 bit OS, you'll already know.

Ah I think the 64 bit issues are all but ironed out at this stage. I've been running 64 bit in work for several years now and all the stuff that was a problem before (flash etc.) have slowly but surely disappeared.

Rockn

Khannie wrote: »

Is there not a performance hit for that? I remember with the "bigmem" kernels there was.

I've no idea but the PAE kernel is the default in Ubuntu, Fedora and other distros now so I guess it's ok.

noshankus

Khannie wrote: »

Ah I think the 64 bit issues are all but ironed out at this stage. I've been running 64 bit in work for several years now and all the stuff that was a problem before (flash etc.) have slowly but surely disappeared.

+1

Naikon

Adobe STILL don't have an acceptable 64 build of Flash on Linux with hardware acceleration. Xv/vdapu or similar drivers combined with mplayer and gecko mediaplayer does a far better job than flash in my opinion. It's beyond a joke at this stage.

I have been running 64 bit for over 3 years now. If you have the hardware, why not? At least you don't have to worry about the '2038 problem'

pickarooney

If the PAE kernel is the default in Ubuntu does that mean from 11.04 onwards?

I'm tempted to install it on Maverick but am always a bit wary of things blowing up.

Rockn

The PAE kernel was installed by default when I installed Maverick on a new build last year. That's how I found out about it. I think you said in another thread that you moved a harddrive from an older computer to your new build which would be why you don't have it?

pickarooney

I'd reinstalled Maverick from scratch only a week or so before moving the hard drive across. Strange. Maybe I have it and it needs some other configuration to take the 4GB into account?

Rockn

Oh when I said 'by default' I meant by default on machines that support it. If you installed Maverick on a computer with less RAM and then moved the HD you'd have the standard kernel. Would that be it?

pickarooney

That would make sense. Thanks.

pickarooney

With the PAE kernel installed now I've got 3.9GB

Thanks all.