What is the Difference Between a 32-Bit and 64-Bit Operating System?

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  • Written By: John Lister
  • Edited By: Lindsay D.
  • Last Modified Date: 12 November 2018
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Today’s PCs come in two varieties: those running a 32-bit operating system and those running a 64-bit operating system. The difference is the amount of information the PC’s processor can handle at any precise moment. While a computer designed for this type of operating system has vastly more potential computing power, it requires fundamental changes to the way its software is designed.

The word "bit" refers to the way computers deal with information in binary, where all data is listed as a string of digits which can either be a 0 or a 1. Each of these digits is known as one bit, meaning a 32-bit processor can process 32 digits at once. Don’t confuse this with memory, which measures the total amount of information a computer can remember without needing to use a storage device such as a disk. While the figure for memory will be much bigger, a computer can’t process all of that information at once.

The software for a computer with a 32-bit processor, including operating systems such as Windows, has to be specifically written to match that processor. The same applies to 64-bit processors. Microsoft produced 32-bit and 64-bit operating system editions of Windows XP and Vista, and will do the same for Windows 7.


There are also some significant mathematical limits to the two different types of processor. A 32-bit processor can only work with a maximum of 4GB of memory, and this is usually limited to 2GB for any one program. A 64-bit processor could theoretically work with 17 billion GB of memory. A 64-bit processor can also carry out some tasks twice as quickly.

The memory limitations of a 32-bit processor started to become clear with Vista, which uses a large amount of memory and can make it difficult to run multiple programs at once without using up even a full 4GB of memory. Meanwhile, it once seemed impossible that any one program would need more than 2GB of memory, but some modern video games have hit that limit. For these reasons, 64-bit processors will likely start to become much more popular, which will increase the number of consumers interested in buying a 64-bit operating system.

The 64-bit editions of Windows can run some software designed for the 32-bit edition through a special compatibility mode, but the results can be very varied. Using a 64-bit operating system can also cause problems with drivers. These are small pieces of software that coordinate each hardware device with an operating system such as Windows.


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Post 32

So which is the best amongst 64bit and 32 bit?

Post 31

Completely wrong. Intel CPUs have supported PAE since 1995. 32-bit Pentium Pro supported up to 64 GB RAM.

A 32-bit Linux supports as much RAM as you can stick to the motherboard. Mine boots up happily with 48 GB and can use it all just fine. Per process is limited to 3 GB at once.

The 32-bit Windows natively supports also way more than 4 GB, but most versions are limited to something lower. 4 GB is an arbitrary choice. This limitation can actually even be removed. Some bad drivers may have trouble with this, though. Most work fine.

Still not convinced? Check how much RAM 32-bit Windows 2008 supports.

The 4 GB myth is strong, but it's really only a myth.

Post 28

The 32 bit will still be the best for many years.

Post 27

My 64 bit win 7 gives a print command slowly when I connect to the printer installed on xp 32 bit in a server domain environment.

Post 26

An HP laptop has 40 HDDl; 512 memory; bluetooth;

pentium M.

Do you advise me to buy it for autocad program running?

What other things should I consider before buying it? Please advise me.

Post 24

ankit198 - it depends of CPU. My Intel Core i3 can support up to 16 Gb of RAM.

Post 17

thanks for the information.

Post 16

please tell me about 32-bit 86x.

Post 13

Does unix have this option?

Post 12

very good article. Thanks for sharing.

Post 10

right click-properties-run in compatibility mode.

Post 9

wow that was an excellent article. Now i am familiar with 32-bit and 64-bit systems. Great.

Post 7

what about java application? Does a java application depend on bit or not?

Post 6


Post 5

Good article, as it states that 32bit OS supports max 4gb RAM while we install 4gb RAM on 32 bit OS machine and it showing only 3gb usable. why?

Post 4

Very informative article, and I think I now understand. So I should have no problem converting a machine from a 64 bit OS to 32 bit OS should I need to downgrade (ie Win 7 64 to Win XP 32)?

Post 3

The article states: "A 64-bit processor could theoretically work with 17 million GB of memory."

Post 2

I have a 32 bit CAD program I want to try loading to operate on my 64 bit 8 MB RAM machine (Dell Vostro 1720. Where shall I look to find a setting, "compatibility mode"?

Post 1

very good article but how many GB memory support by 64 bit processor?

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