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t60 memory question

Posted: Fri May 08, 2009 1:11 pm
by period3
I have a T60 with a 2GHz T2500 processor and 3GB of memory.

I'm constantly running out of memory. As it stands, I don't think I can use more than 4GB of memory (3GB physical + 1GB virtual).

Is there a way to get Linux to use more than 4GB of memory on this laptop (I realize only 3GB will be physical). Presumably, my 32 bit CPU limits my virtual memory as well.

IF it's not possible, what if I upgraded my CPU to a core2 duo? Though I'd still be limited to 3GB of memory due to chipset limitations, would I then be able to address larger amounts of virtual memory?

What about PAE - would that enable Linux to address more than 4GB of physical+virtual memory with my current processor?

(EDIT: Forgot to mention that I need all of the memory addressable by a single process - so that might rule PAE out unless Linux has something like Address Windowing Extensions on windows...)

Thanks

Re: t60 memory question

Posted: Wed May 13, 2009 9:59 am
by whizkid
I suggest you ask this question on the forum for your Linux distribution, or a generic Linux forum.

My hunch is that you will need a 64-bit CPU (upgrade to Core 2), a 64-bit OS and a 64-bit application. That might do the trick to give your code a 64-bit virtual address space.

I'm sure you're aware that trying to use a working set much larger than physical memory will severely affect performance.

If you'll be doing a lot of this kind of work, upgrading to a machine that can use 8GB or more of RAM could be worthwhile.

Re: t60 memory question

Posted: Thu May 14, 2009 4:20 pm
by madcow
The answer is No. It's a hardware limitation, not the OS.

If u really need 4 G or more RAM, switch to a T61.

32 bit Linux can support up to 64 G of RAM.

I'm using 4 G of RAM on a 32 bit Ubuntu (had to use the server kernel).