What Is The Difference Between 32-bit & 64-bit Windows?

People ask me on a daily basis, “What is the difference between a 32-bit and 64-bit Windows operating system?” Most of you are running Windows XP or Vista in its 32-bit iteration. But as hardware gets cheaper, people are curious as to what the 64-bit operating system has to offer. First let’s see if we can grasp the difference between 32- and 64-bit.

Think of your computer as a series of tubes that can either be 32 or 64 bits wide. When you have the smaller 32-bit size, there is more potential for bottlenecks to occur. Bottlenecks slow down your system because one process has to wait for another to finish before it can begin. But if you want to have 64-bit wide tubes, your computer needs to be thinking in 64-bit so your software and hardware all need to support 64-bit.

If you do not know the difference between 32-bit and 64-bit, I would have told you in the past that you are running a 32-bit version of Windows. But now with Windows 7 I am seeing more and more 64-bit operating systems shipped by default without the end users knowledge. Don’t get me wrong, a 64-bit system is better but you also need to be running 64-bit programs and have a 64-bit processor or else all the trouble of setting up the 64-bit operating system would be worthless.

On a 32-bit operating system, you are restricted to a maximum of 4 gigabytes of RAM. On a 64-bit operating system, you really do not have a limit. Let’s look at Wikipedia and find out the maximum amount of RAM for a 64-bit operating system:

2⁶⁴ addresses, equivalent to approximately 17.2 billion gigabytes, 16.3 million terabytes, or 16 exabytes of RAM.

That is a huge amount of RAM! Normally when you exhaust your physical RAM on a 32-bit system, it has to use virtual memory or hard disk space to pick up the slack. On a 64-bit system, you can install as much RAM as you can to cover your overhead. From here on, 32-bit operating systems will be referred to as x86 and 64 bit operating systems as x64. You can tell what you are running by right clicking on My Computer and choosing Properties.  Below is a shot of a 64-bit machine using 12GB of memory.

And in this shot, we see a 32-bit machine trying to use 7GB of RAM.. Not going to happen!

If you are running 3D modeling systems or AutoCAD systems, you can benefit from a x64 bit architecture but remember, you need to be running ALL x64 applications, print drivers and anything else you are setting up on your system to realize its full potential. Not all programs have been created for x64 yet and you will find yourself installing applications to your Program Files x86 directory. On a x64 machine, you will have two Program File directories — one for 32-bit and one for 64-bit applications.

So after reading through that and you still want to run a x64 operating system, you will need to make sure your processor supports x64. Most new servers and new computers bought this year or beyond will support x64 but you will still need to check. Here are some facts you should know (taken from ZDNet):

• Almost all new servers sold within the last two years from AMD or Intel will have x64 capability.
• Most mid- to high-end desktop processors from AMD or Intel within the last year have x64 capability.
• Some higher-end Semprons have x64; lower-end Semprons do not.
• No AMD Durons have x64.
• All AMD Opteron processors have x64.
• All AMD X2, FX, and Athlon64 chips have x64.
• All Intel Pentium D and Celeron D chips have x64.
• All AMD Turion notebook processors have x64.
• All Intel Core 2 processors (mobile, desktop, and server) have x64.
• No Intel Core Duo notebook processors have x64
• No Intel Pentium M notebook processors have x64.

If you are still not sure if your processor can support x64 check out GRC’s SecurAble and let them help you figure it out!

If you are running a server that has all its hardware and software certified for x64, then you should install the 64-bit version but beware of device drivers and any 32-bit environments because if I used the word difficult, it would be an understatement!