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Possible Duplicate:
Ubuntu 64-bit vs 32-bit

Hi,

I currently run a Ubuntu system with 32 bit but I have 4 GB of RAM. As I have heard only 3 GB are used. In the recent time I'm seeing that I need more memory. The question is: Should I change to Ubuntu 64 bit? I heard that with a 64 bit system you need twice as much memory as with a 32 bit system so effectively I would have less memory?! In the near future I plan to upgrade my RAM to 6 GB or 8 GB but this wouldn't pay off significantly if this was true, right?

I have seen related questions on this topic, but they weren't that specialized on the memory issue... But if I understand it correctly it also depends on the Applications used: On my computer a lot of memory is used by Web browsers (Chrome, Firefox). But I also use Eclipse and often use VMWare (Windows XP with 1 GB) That sometimes really slows down my system, in particular the VM becomes slow... And I am now working on a project that needs Hadoop, this might also need a reasonable amount of memory...

So my question is: Does it pay of to switch to Ubuntu 64 bit? Or would I need at least 8 GB or 10 GB of memory to have a reasonable payoff?

Thanks, Philip

Community
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Philip
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3 Answers3

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It pays to switch.

See the following questions on SU:

Community
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Tyler
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In my experience the idea that a 64-bit install takes twice as much memory is rubbish.

What you really need to figure out is if the 3GB limitation is really a problem for you. A technology called Physical Address Extension allows a 32-bit processor to address up to 64GB of RAM. It may not be enabled in Ubuntu by default, but Ubuntu is uses a kernel with support. Check out this article: https://help.ubuntu.com/community/EnablingPAE

Your operating system is currently addressing 3.37GB (give or take) of your RAM, so by switching to 64-bit or enabling PAE you'd gain something like 768MB.

Of course, there's a performance benefit to a 64-bit operating system that means the upgrade is worth it for non-memory reasons.

jcrawfordor
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I dont think the memory usage will increase with CPU architecture. The 64bit Linux is capable of handling morethan 4GB of memory. But the 32bit kernel is also able to handle that with PAE ( Physical Address Extension ). The memory usage in the system depends on the application that you are using. Also before switching to 64bit, you need to check that the applications that you are using are available in 64bit architecture.

Unni
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