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how to know if a computer is 32 bit or 64 bit

32-bit v/s 64-bit systems


This 32-bit and 64-bit thing baffles me. It's not often that I run across it, but when I do, it baffles me. Like when I want to download software from it asks me which version to download.

I have win XP running on my thinkpad machine. How do I find out if my hardware is 32-bit or 64-bit. Also, how do I find if OS is 32-bit or 64-bit and thus how to know which version to download from this link. Also for any installed application say firefox, how do I know which bit version is installed.

How popular are 64-bit hardware/OSs?. Are all the new CPUs and OSs supporting 64-bit and 32-bit for backwards compatible or 64-bit is still a luxury?


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marked as duplicate by BloodPhilia, Sathya Feb 13 '11 at 13:13

This question was marked as an exact duplicate of an existing question.


Here, this: how to find out.

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To get you started you can find out your operating system by going to the start menu, right clicking on 'My Computer' and then click 'properties'. If you don't see the 'x64 edition' listed, then you are running the 32 bit version of windows. If 'x64 edition' is listed under 'System' then you are running the 64 bit version.

If you are running the 32 bit version of windows xp then download the 32 bit version. I don't think you can run the 64 bit version of windows xp unless your hardware allows it. If you are running 64 bit version of windows you should be fine downloading the 64 bit version.

Unfortunately I don't know much about the current trends in 64 bit hardware or how to tell if your computer can upgrade to 64bit windows, but hopefully this helps you in the right direction.

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Modern processors are all 64 bit. Modern OSs are available in 32 bit and 64 bit variants (Windows XP is not a modern OS, but it is very popular, so Microsoft released a 64 bit variant).

64 bit processors are perfectly compatible with 32 bit operating systems, but 64 bit operating systems are not backwards compatible with 32 bit applications per se, although most 32 bit applications can be run on 64 bit systems with some tricks.

On a desktop computer, the main reason for having a 64 bit OS is the RAM. A 32 bit OS cannot use more than ~3.5 GB memory (here "memory" is the sum of system RAM, graphic card RAM and some firmware chips on the mainboard and the extension boards). Computers sold nowadays usually have more than 3 GB RAM, so for them, a 64 bit OS isn't a luxury, it is a necessity. And in the future, the share of 64 bit applications will grow and the share of 32 bit will shrink, so if you are buying a computer right now, there is no sense in getting a 32 bit OS. But if you already have a 32 bit OS, there is no need to change to 64 bit, unless you have some very good reason to upgrade your RAM.

As for how to check which you have, just go to Control Panel and open System. It will tell you whether your current OS is 32 bit or 64 bit. If you don't want to upgrade, use the knowledge to decide which program versions to download and keep it at that. If you plan to upgrade, you'll see your processor type listed there, for example, "Intel Core2 Duo T9300". You can then look on the Internet whether the processor supports 64 bit or not.

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Thanks. Mostly people are telling about how to check bit-ness of OS. How to check bit-ness of hardware as well? My processor is T2300@1.66 GHz. – p2pnode Feb 13 '11 at 13:10
There was a way, you'd need to open the Registry and look up a specific entry containing the stepping, only I don't remember which entry. I find it easier to look up the properties of the processor on Wikipedia. As I said, on Control Panel -> System, you see your processor model, the one in my laptop is T9300. If you search on Wikipedia for Intel T9300, you find the article "List of Intel Core 2 microprocessors", which starts with the words "The Core 2 brand refers to Intel's x86/x86-64 microprocessors", so 64 bit. You can also google how to find out your processor stepping in the registry. – rumtscho Feb 13 '11 at 13:21
T2300 is 32 bit, – rumtscho Feb 13 '11 at 13:24

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