Why would Ubuntu as a generalized statement recommend its 64 bit “flavour”?

As far as I understand a 64-bit OS can only be installed on a 64-bit hardware (CPU), i.e. 32-bit and 64-bit OS can be installed on a 64-bit hardware, but only a 32-bit OS can be installed on a 32-bit hardware (regardless of the amount of RAM available).

You can see this on the download site:


I understand the difference between 32-bit and 64-bit, and I see the pros and cons. For users with a 32-bit hardware this is not a question of choice. Recommending a 64-bit OS without taking into account the hardware is like recommending petrol over diesel and neglecting the engine. The download site does not check for 64 bit processor hardware, and if detected recommend a 64-bit OS, but recommends a 64-bit OS to all users (with more than 2 GB RAM).

It has been stated that ”manufacturers don’t really make 32-bit systems any more” (Dalton), and that “almost all chips in recent history are 64 bit” (oldfred). This is true at least for processor families in TOP500 supercomputers. So this recommendation simply reflects a trend in industrial production?


Most modern computers come with more than 4GiB of RAM, so you'd need a 64bit OS to use all of this. (Or 32bit with PAE, which is slower) Also, most new machines are using UEFI, and Ubuntu 32bit ISO's aren't UEFI-capable, so here you'd have to go with 64bit

On older hardware, which doesn't use UEFI and/or has less then 4GiB of RAM, it doesn't matter, as long as the CPU is 64bit-capable, which most are.

Other than that, 64bit may be recommended for various reasons:

  • You can run 32bit software on a 64bit CPU (multiarch), but not vice verca. So you may be better off with 64bit when talking about software compatibility.
  • If people don't know the difference between 32bit and 64bit, the should choose the one that will run on the most systems with less problems, which probably is 64bit. Although someone might say that people should know the difference when installing an OS by themselves, I've met at least one person who wanted to install Ubuntu and had barely any clue of CPU architecture ("64bit is better, because it's the greater number" should indicate his knowledge)

There may be other reasons, but these are the ones I can think of now.

  • With 32bit PAE can be used for more than 4GB of RAM - I used to have this with nearly every flippin netbook. – Wilf Nov 30 '14 at 17:37
  • @Wilf yes but that was merely a patch. Your system with PAE would be a bit slower. If you install the 32 bit you will still get PAE with 4Gb+ but why bother if the 64bit version is better in everything. – Rinzwind Nov 30 '14 at 18:35
  • You can run a 32-bit OS on an UEFI computer. Just not Ubuntu, as the UEFI bootloader has not been put in the Ubuntu .ISOs. There are 32-bit only UEFI machines, and there are operating systems that have 32-bit versions that boot using UEFI. – John Scott Nov 30 '14 at 18:53
  • @FuzzyToothpaste Really? Never heared of that. I'll include it in my answer. Coul you provide any example? – s3lph Nov 30 '14 at 18:57
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    @the_Seppi an obvious example of a 32-bit OS that supports EFI would be the early versions of OSX for the Mac-intel platform. – Rob Moir Nov 30 '14 at 19:22

It recommends it because 64-bit is faster and today, manufacturers don’t really make 32-bit systems any more. It may also recommend 64-bit because the download site recognized that your pc is 64-bit (the one you are using to download the image). It also says 32-bit is for PC's with less than 2GB of ram because 99.9% of all PC's with less than 2GB of ram are 32-bit. Take it as you will, but 32-bit is being phased out and is mostly on old slow hardware. Ubuntu is not made for outdated hardware, I would use something like xubuntu or lubuntu if you planned on putting on on outdated hardware.

  • - You state that ”manufacturers don’t really make 32-bit systems any more”. What is your source e.g sales figures? - Assuming manufacturers had suddenly stopped producing 32-bit systems 3 years ago – how would this reflect in the number of systems in use? I have done a quick search and not been able to find any data on this. - I don't think the download site recognizes my systems's hardware – it's 32-bit... ;-) – marianoju Nov 30 '14 at 18:28
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    @mariano purely from a logical point of view: any system sold with W7 or W8 will be 64bit. Do you still see new system in store that sell with another operating system? – Rinzwind Nov 30 '14 at 18:36
  • @Rinzwind Yes I do see “new system[s] in store that sell with another operating system”, but I don't have numbers. So I can only speculate. But maybe someone has them. Do you by any chance? – marianoju Nov 30 '14 at 18:49
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    Ubuntu will be phasing out 32 bit with 16.04. summit.ubuntu.com/uos-1411/meeting/22353/… Note that almost all chips in recent history are 64 bit. There were only a few Atom's that were 32 bit more for Windows tablet type systems to try to prevent Linux installs: en.wikipedia.org/wiki/X86-64 – oldfred Nov 30 '14 at 18:54
  • The other reason for the recommendation of 32-bit on <=2GB RAM is that a 32-bit OS uses less memory in general, so even if the CPU is 64-bit, if the system is RAM-constrained, you might get more real-world performance (avoiding swapping) by running it as 32-bit. – hobbs Nov 30 '14 at 22:23

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