How do you determine that your hardware is 64 bit capable when there is no operating system installed?

  • 6
    @ChrisO How do we know it's Intel? Or, if it is, that is was manufactured recently?
    – user160790
    Dec 21 '14 at 9:17
  • 5
    @ChrisO > all been 64-bit capable since the last 15 years or so ... hardly, the first ever x86-64 CPU, intended for servers, was released eleven years ago (2003). Most consumer CPUs did not support x86-64 until 2004-05. And even now there are fairly common CPUs that do not support it.
    – Bob
    Dec 21 '14 at 23:12
  • @ChrisO: The question clearly states that there is no OS installed. Dec 22 '14 at 1:33
  • 1
    @ChrisO: The entire point of the question is to find out how we determine the 64bitness of the CPU without those assumptions in place. Dec 22 '14 at 16:16
  • @ChrisO It is ridiculous to say that the question clearly states "no installed OS", and then try to infer that an OS could be installed because it is a "weak question." Is there a name for the opposite of assuming the conclusion? Oh yeah, paradox.
    – Kyeotic
    Dec 22 '14 at 18:06

Open up the computer and look at your CPU and motherboard to get the model numbers, then look them up at the manufacturers (i.e.: Intel, AMD) and check the specifications provided.

Alternatively you could boot from a Linux LiveCD or alike and use that OS to detect the capabilities (no OS installation on the machine required).

  • 5
    Looking at the CPU would require removing the heatsink and removing all the thermal compound, long and messy operation (plus you'll need new compound to reinstall the heatsink).
    – user256743
    Dec 19 '14 at 21:46
  • 2
    @AndréDaniel While I agree with your point, I find it hilarious that one person suggests taking off the heat sink and replacing compound is hard, yet so many others suggest "overheating? yank your heat-sink and replace the compound!" as the first option. Thermal compound is $5 and easily avialable, and in 99% of the cases you don't actually need to replace it if all your doing is taking the heat-sink off and putting it right back on. Anyhow, yeah if the BIOS tells you, even better. ;) Dec 19 '14 at 21:57
  • 2
    By hard I mean hard enough for someone asking such a trivial question on SU. ;)
    – user256743
    Dec 19 '14 at 22:00
  • 2
    Sad but true. :(
    – user256743
    Dec 19 '14 at 22:05
  • 5
    @Ƭᴇcʜιᴇ007 you will have to replace the thermal compound if you really want to be able to read what's inscribed on the CPU. Otherwise all you'll "read" is the surface of the compound.
    – Ruslan
    Dec 20 '14 at 12:12

Look in the BIOS, they often display a summary of the installed hardware including the CPU model, you can then search that on the web and see if it's 64-bit compatible.

Alternatively, if the computer is of a known brand and not a custom-built one, you can search for its model and you'll find a lot of info on it, like the CPU that's in it (then do what I said just above).

  • Note that it's possible (quite common) for computers of big brands to be customisable under the same model number. To start with, manufacturers like Dell offer easy customisation when you order. Then someone could decide to replace parts of the hardware at any time. It's a good start, but cannot be relied upon.
    – Bob
    Dec 20 '14 at 2:29
  • @Bob the CPUs will still be similar in terms of specifications, while the number of cores or frequency may vary it's unlikely that some CPUs will only be 32-bit and others will also support 64-bit... Either the machine is really low-end in which case they stick with 32-bit Intel Atoms or they go higher (Pentium Dual Core, i3, etc) in which case they're all 64-bit compatible.
    – user256743
    Dec 20 '14 at 2:38
  • 3
    You're assuming current-gen Intel hardware. Older generations provided both options on a single socket type (e.g. LGA 775), and other x86 manufacturers could decide to do the same (I'm not familiar with the specifics of those others, but the possibility is there). Basically - you can guess based on the whole-machine model, but you cannot always be certain.
    – Bob
    Dec 20 '14 at 3:35

Build a USB key with a 64-bit flavor of Ubuntu and boot into it. By default it will not modify anything on the computer itself.

  • 1
    What if the machine is 32 bit machine? Please provide the steps using which the OP can find out if the hardware is 64 bit capable or not
    – Prasanna
    Dec 20 '14 at 14:36
  • 17
    If the machine is 32-bit, booting 64-bit Ubuntu will produce an error message along the lines of "this kernel requires an x86-64 CPU but only detected an i686 CPU".
    – nandhp
    Dec 20 '14 at 17:06
  • 3
    @Prasanna you can find all the supported instruction sets on the CPU regardless of operating systems, so you can run a 32-bit OS and check if AMD64, EMT-64, x86_64 or whatever flag is available on the CPU
    – phuclv
    Dec 21 '14 at 7:03
  • By definition this doesn't answer the question as the operating system is installed onto a USB drive.
    – AStopher
    Dec 22 '14 at 17:56
  • @cybermonkey: "OS installed," here, means something deployed as part of the machine's infrastructure (e.g. on a HDD) and allowing complex and full functionality. Though ostensibly "installed" on flash or optical media, the "linux lite" is clearly categorically different. It is a stripped-down OS whose purpose is little more than to provide a platform for system diagnostic tools, and is deployed in pre-configured form requiring perhaps 10 minutes of preparation. Not only does it provide a quick and precise answer, but will do so if components cannot be identified visually. Dec 23 '14 at 10:27

Unless your hardware is ten or more years old, it's virtually certain to be 64-bit capable -- all Intel and virtually all AMD x86-compatible processors made in that time frame have been 64-bit. Most processors for Android devices are 32-bit, but since most of those machines can only run Android anyway, it's less of an issue with them (and if you have a single-board computer like a Raspberry Pi, you'd probably know that from buying it or can look it up by the device model designation).

  • 1
    Note that 64-bit ARM processors just became a thing. And, as far as I know, there are no consumer-land 64-bit Android devices yet.
    – HalosGhost
    Dec 21 '14 at 15:28
  • 1
    And, based on other answers, there is apparently a family of 32-bit Intel Atom processors still in production for netbooks and similar machines -- but for desktop and full laptop machines, if it's less than about 10 years old, it's 64-bit capable.
    – Zeiss Ikon
    Dec 21 '14 at 16:46
  • @HalosGhost: The Nexus 9 is 64-bit.
    – bwDraco
    Dec 21 '14 at 18:33
  • 1
    @DragonLord, I stand corrected then. Though, that device just came out.
    – HalosGhost
    Dec 21 '14 at 18:40

If your processor is any non-ancient flavour of x86 processor, you can use the CPUID instruction. On modern processors, you can use it to find out if your CPU is 64 bit capable. On older processors, you can use it find out if you can ask the processor whether it is 64 bit capable; if you can't ask it then it isn't. If you look deeper into Intel's and AMD's manual, there is code running on even older processors that allows you to check whether the CPUID instruction is available; if it isn't then again your processor isn't 64 bit capable.

  • Absolutely...getting a CPUID dump of a system tells you basically everything you need to know. But it should be pointed out that it is a small program requiring an OS to run. This is another point in favor of employing a lite linux distro bootable from usb or disc: the availability of full-system information readout tools. Dec 23 '14 at 10:49

You shouldn't even need to turn on the machine, look for the model number on the back of the case. Unless it is truly a white box PC, you should find a model number or even a serial number. Search the web or call the manufacturer.

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