Lately I noticed that my old laptop (Toshiba Satellite L500-1DT) works better with x64 based Ubuntu version, than x32. Well with faster I meant - Adobe Flash videos and apps works much better. Software Center and APT apps works much smoothly. Everything works flawless on x64. Cooling fan works a lot less (not cooling the system all the time, like on x32). On x32 bit version I had a feeling, that my computer will overheat. 2 weeks ago my battery died when I ran x32 version. I don't know, is it was because of overheating or coincidence. It got REALLY hot, and very very slow. I'm running on Celeron(R) Dual-Core CPU T3000 @ 1.80GHz × 2 and Intel GMA45 video chip-set (with 256mb shared memory). RAM - 4 GB. Ubuntu 11.10.

This is not the only case and only machine i discovered that x64 works FAR more better, than so-called "Recommended 32-bit version". I'm really curious about this, and would like to know answer once for all.

Please, explain this to me or guide me with a link.

Thank you !

  • ubuntu forums - The '32-bit recommended' bug was a decision made by the web design team, not Ubuntu developers, nothing to do with flash, etc. The whole sordid story is here if anyone is interested: bugs.launchpad.net/ubuntu-we...nt/+bug/585940
    – Ringtail
    Mar 18, 2012 at 0:43
  • If you are using a 64bit machine use a 64bit OS
    – Ringtail
    Mar 18, 2012 at 0:44
  • the launchpad link doesn't works ... Mar 18, 2012 at 0:58
  • bugs.launchpad.net/ubuntu-website-content/+bug/585940
    – user12753
    Mar 18, 2012 at 1:04
  • 1
    I don't think you really mean "x32". There's isn't a version of Ubuntu released for the "x32" architecture AFAIK. May 13, 2015 at 9:44

4 Answers 4


Uh, "twice as fast if not more depending on the hardware it runs on"?? Ah, if only the world worked this way.

For example, take a look at this article: Ubuntu 12.04 LTS: 32-bit vs. 64-bit Performance. While some of the synthetic benchmarks show drastic performance gains, there are also many which show either just minor (10% to 30%) gains, no gains, or even a performance decrease. And those are just synthetic benchmarks which usually does not give useful insight into what the system performance will be when doing something other than running benchmarks.

System performance is very much influenced by "system" bottlenecks and you can't make sweeping generalizations such as twice the bits implies twice the performance.

Having said that, I still try to use the 64-bit flavors of operating systems because I expect the performance to be at least somewhat better. While the size of the CPU registers is doubled, possible of more importance is that the number of registers increases from eight in x86 to sixteen in x86_64 64-bit mode. This allows a compiler to potentially produce faster code. There are a number of these instruction tweaks which, while probably insignificant in any one instance can add up when used system wide to a useful performance gain.

There is also little if any performance loss for programs compiled for 32-bit x86 since they can be run in "compatibility mode".

People often make the generalization that if you only have 4GB or less of memory then there is no difference between 32-bit and 64-bit and thus no reason to use the 64-bit version. This is simply not true. The instruction architecture of the CPU is different enough (IMO) in 64-bit mode to prefer using the 64-bit OS if your hardware supports it.

After all, you wouldn't want to run your 32-bit CPU in 16-bit mode, would you? :-)

  • In particular, pointers are twice as big and use twice as much memory (and bus bandwidth), and this can be bad for programs that use a lot of pointers, such as Python. But in general, yes, 64-bit is a better default.
    – poolie
    Oct 24, 2013 at 10:00
  • Great comment overall, though I would definitely disagree with this sub-statement within your overall statement (which I do agree with =)). ........ "there are also many which show either just minor (10% to 30%) gains" a 30% gain in performance considering the number of bottlenecks that can and are present in a personal computer is a very good gain still imo.
    – Josh
    Nov 11, 2014 at 21:38

In short: more operational registers are available in x86_64 mode comparing to x86. Also, there's confusingly named x32 ABI which isn't x86(_32) but rather mix of x86_64 and pure x86. And, BTW, the article I gave you link to has good explanation why x86_64 is tend to have higher performance.


Such an extreme difference is not typical and not really related to any general advantages of 64-bit mode.

I suspect you're seeing either some kind of bug related to your hardware, or a bug in your device's firmware that's triggered by Ubuntu's 32-bit kernel.


64-bit OS operate twice as fast if not more depending on the hardware it runs on. Going from 32-bit to 64-bit increases the OS's ability to process larger chunks of data. Therefore it operates much faster. Also, 64-bit OS will use more memory than a 32-bit OS. A 64-bit register can store 264 = 18446744073709551616 different values, a number in excess of 18 quintillion. At the moment x86-64 processors use 48 physical address lines; therefore a processor with 64-bit memory addresses can directly access 264 terabytes of byte-addressable memory.

  • 4
    'operate twice as fast if not more' - not necessarily true. Some algorithms are specifically designed to have 32 bit words. AES for example. Mar 18, 2012 at 5:02
  • I think, more or less, I had my answear ! Thank you all !!! Mar 18, 2012 at 10:25
  • @marchindeed: Welcoming you to AskUbuntu, I'd like to encourage you to mark this question as solved, by using the grey/green circular button left to this answer - this will both praise Petronilla, and make it easier for others with the same question to find the answer. And by the way: that's a nice question! Mar 30, 2012 at 19:44
  • 1
    This answer identifies best case scenario improvements of 64-bit over a 32-bit, but irrational John's answer identifies the practical reasons a 64-bit processor tends to perform better in real life. Also, remember that a 32-bit processor can address quite a bit of memory with Physical Address Extension, which Ubuntu fully supports, though it's somewhat less efficient than having a 64-bit processor to address it "directly." See also help.ubuntu.com/community/32bit_and_64bit. Apr 22, 2012 at 20:08
  • I have no idea how to close this disscusion ! Apr 26, 2012 at 12:38

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