Washington - Crack open a new copy of Windows Vista, and you'll be faced with a decision you haven't had to make in the past: Should you install the 32-bit version or the 64-bit one?Both versions are included in the standard Vista retail package, but few people know what the difference is, or why you would install one version over the other.
The riddle isn't relegated to Vista alone, however. Windows XP now comes in a 64-bit version, as do other operating systems, and a growing number of applications are being readied for 64-bit computing, as well. In some cases, you'll need to know at the time of purchase which version you want.
--- What's the difference?
The main difference between 32-bit and 64-bit computing lies in the central processing unit (CPU), the main chip that's at the heart of every computer. 32-bit processors can handle 32 bits of data at a time, while 64-bit processors, as you might imagine, can handle twice that amount. In short, when a processor can handle more data, it can theoretically allow you to load larger programs, bigger files, and generally be more productive. Most processors sold in computers today are 64-bit but also fully support 32-bit instructions, which makes them compatible with the majority of today's operating systems and software.
But the handling of "bits" tells only part of the story. Access to computer memory is another major difference between 32-bit and 64-bit processors. 32-bit processors can access a maximum of 4 gigabytes (GB) of system memory (RAM). While 4 GB of memory used to seem like more than anyone would ever need, many of today's PCs can easily hold 8 GB or more. Unfortunately, no matter how much physical memory you put in a PC, if you are using a 32-bit processor or a 32-bit version of Windows, you'll be able to access only the first 4 GB.
64-bit operating systems can access much more computer memory than 32-bit operating systems, which means you'll be able to do work on larger files, more files, or with more applications open at once than you could with a 32-bit operating system. How much more than 4 GB of RAM you a computer can access depends upon the operating system. Vista Home Basic supports 8 GB, Home Premium 16 GB, while Ultimate, Business, and Enterprise editions all support 128 GB or more. The 64- bit version of Windows XP can access at least 128 GB of RAM.
--- Are 64 bits better?
You might think that a move to a 64-bit operating system and 64- bit applications will make everything run twice as fast. Unfortunately, you'd be wrong. While a 64-bit environment does run more efficiently, assuming you have sufficient computer memory, you won't notice the same kind of speed boost that folks saw when they went from 8-bit to 16-bit years ago.
In addition, a lot of factors influence how fast a 64-bit computer actually runs. For instance, if you run applications designed for a 32-bit processor on a 64-bit operating system, you won't see the same kind of performance improvement that you would if you ran a 64-bit application on a 64-bit processor.
--- Compatibility
So will you have to purchase all new software if you adopt one of the 64-bit operating systems on the market? Not necessarily. The 64- bit versions of Windows, both XP and Vista, will run most 32-bit applications just fine. Applications that were designed from the ground up - or re-coded - to run natively on 64-bit operating systems will run the best, utilising all of the memory and processing resources of 64-bit computers most effectively. But you can transition to those applications while continuing to use what you have installed now.
Device drivers are another story, however. Windows users will have to make sure that the manufacturer of whichever peripherals you connect to your computer - printer and scanner, for instance - provides 64-bit drivers. If not, you'll have to try to rely upon the limited number of drivers that Microsoft provides with it 64-bit operating systems. In a worst-case scenario, you may have to do without a peripheral or two - or purchase new ones that have the necessary drivers.
Mac users are better off. The standard version of Apple's Mac OS X (Leopard) is 64-bit and includes abundant drivers.
--- Can you upgrade?
If you want to go from the 32-bit version of Windows Vista to the 64-bit version, you'll have to do so by reinstalling the operating system from scratch, using the 64-bit installation DVD. You can't "upgrade" to the 64-bit version the same way you can upgrade from, say, Windows XP to Windows Vista just by popping in the DVD and clicking the "upgrade" option.
If you intend to install the 64-bit version of XP, Vista, or another operating system, make sure that you are ready. Have at least 4 GB of RAM in your machine in order to take advantage of the environment's ability to access much more RAM. Also ensure that you have all of the necessary 64-bit drivers for any peripherals you intend to attach to your PC. For Windows Vista, it's a good idea to read through Microsoft's "installation choices" overview for 64-bit versions of Vista.
