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148. The 64 Bit Question

By Andrew D. Wright

If you've bought a new computer since 2005, you've probably got a 64 bit processor even though you're still running a 32 bit version of Windows. So what's up with that?

When you're talking about 32 bit or 64 bit here, what you're really talking about is how big the computer's work space can be, and how much data can be chewed through with each processor bite.

With the work space, it's all about addresses. Your computer needs to keep track of millions of different little pieces of data at a time. Each of these little pieces has its own address in memory.

With a 32 bit CPU, there are 2 to the power of 32 addresses, or about 4 gigabytes of memory the processor and operating system can use in total. This is the computer's work space, the limit to how much data it can deal with at a time without having to put something aside.

With 32 bit versions of Windows, several hundred megabytes of memory are reserved for system use. A computer with 4 gigabytes of RAM will have only 3.2 or so gigabytes of RAM it can actually use for tasks.

The advantages of the 64 bit architecture are a vastly increased address space - from 4 GB maximum to 17.2 billion GB (!) - and in practical terms, the ability to run much larger applications in memory without lag.

When it comes to making things go faster, some data intensive tasks can be greatly sped up using 64 bit processors over 32 bit processors.

As a result, in the highly competitive field of processor sales, there has been a great incentive for widespread adoption of 64 bit. Processor maker AMD put out the first commercially successful 64 bit consumer-level CPU in 2003.

Free Open Source operating system Linux offered 64 bit support even before the hardware was available, and all the major Linux distributions such as Ubuntu and openSUSE have both 32 bit and 64 bit versions.

Microsoft came out with a 64 bit version of Windows XP in 2005, and Windows Vista has 32 bit and 64 bit versions. The forthcoming Windows 7 will also offer both versions (though the 64 bit version of the publicly released beta is widely considered the better of the two).

Until the last couple of years, there wasn't anything pushing home users to move to 64 bit operating systems and software. Most home users didn't have 4 GB of RAM and hadn't needed to run anything wanting more resources.

The cheap price of memory and data intensive tasks like editing home movies from your digital movie camera and running the latest graphics-intensive games are starting to change that. 64 bit computing is slowly moving from Power User country into the mainstream.

Windows users making the switch will notice that only 64 bit versions of programs will install to the Program Files folder. All 32 bit programs will install to a folder called Program Files (x86).

Using older software and hardware on 64 bit Windows can be problematic. Some very old programs will refuse to run at all or have problems. All devices need 64 bit drivers, meaning that using any device more than a couple of years old will likely be a problem. There may be issues with some 64 bit drivers and software being flawed early versions and with some 32 bit software occasionally not acting correctly in the 64 bit environment.

Early days or not, the push to 64 bit home computing is gathering momentum and worth keeping in mind when making any new computer related purchases.


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Originally published 13 February 2009


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