If you're planning to invest in new computers, it's worth considering whether to make the move to 64-bit technology. Does the extra scalability justify the expense?

The wave of the future is undoubtedly 64-bit technology. 64-bit processors have been pretty common in high end servers since 2004 and now 64-bit desktop machines are being offered by most PC vendors. Since 64-bit CPUs can handle more memory and larger files, and 64-bit processors are backwardly compatible with 32-bit operating systems and applications, it seems obvious that 64-bit hardware provides you with the ultimate in scalability. If you're in the position of buying new computers in the near future, you may be wondering whether it's worth the expense to go 64-bit. Let's take a look at some of the pros and cons.

What is 64-bit processing anyway?
When we talk about "bits" as applied to computer processors, we're talking about the maximum-size number that the processor's registers can store and handle at one time. This means a 64-bit processor can handle numbers that are twice as large as those handled by a 32-bit processor. Practically speaking, what does this mean to you?

Advantages of 64-bit systems
Just as the transition from 16-bit to 32-bit PCs in the 1980s greatly increased computing power, the leap from 32-bit to 64-bit will double the amount of data that a processor can handle on each clock cycle.

A big advantage of the 64-bit system is its ability to support more system memory. Most computer users know that programs run faster (and you can run more programs simultaneously) if you add more RAM. Unfortunately, 32-bit chips can generally only address 4GB of memory.

There was a time when 4GB of RAM seemed like more than enough memory for any computer, but that's no longer true with today's memory-hungry applications. And it's not just heavy gamers who need lots of memory. The popularity of running multiple servers as virtual machines on a single physical computer has vastly increased the memory needs of those machines, and even on workstations, memory-intensive graphics and video applications, Computer Aided Design (CAD) programs, computer simulation and modelling software and the like are pushing the upper limits of that 4GB ceiling.

64-bit processors, on the other hand, can address enormous amounts of memory â€" up to 16 exabytes. To put that number into perspective, it's equal to over 16,000,000,000,000,000,000 bytes, or 16 billion gigabytes. You can be pretty sure that by the time you need more memory than that, the 64-bit system you buy today will be long gone. Of course, the amount of memory you can install in a system is limited by its motherboard, the number of memory slots it has and the size of memory modules that are available. Many current 64-bit motherboards will accommodate 8 to16GB or more of RAM.

By allowing for the addressing of more RAM, 64-bit processing can greatly improve video encoding and decoding, CAD, VMs and some other applications. But does more bits mean better performance? Well, maybe and maybe not. You'll see a performance increase for applications that use 64-bit integers, but don't expect most of your apps to run any faster than they do on your 32-bit systems. And your web browser will still be limited by your Internet connection speed, your word processing program will still be bottlenecked by how fast you can type, and so on. In fact, there can be a slight performance decrease caused by the switch to a 64-bit processor, because the larger memory address pointers take up twice as much room in the cache.

What's available in 64-bit?
There's little doubt that 64-bit computing will eventually make 32-bit systems obsolete. Major hardware and software vendors are all headed in that direction. Intel shipped the 64-bit Itanium for high-end servers way back in 2001. AMD introduced its 64-bit Opteron and Athlon 64 processors in 2003 and Intel brought out its EM64T line, updating versions of its Xeon and Pentium 4 lines to 64-bit the next year. In 2005, IBM came out with a dual-core 64-bit PowerPC processor that was code-named Antares, and AMD released dual-core 64-bit Opterons for servers and Athlon 64s for desktops. Today AMD also offers the Sempron and Turion 64, Intel has the Itanium 2 and other platforms, such as MIPS, SPARC and HP's PA-RISC, also support 64-bit computing.

Linux was the first operating system to run on Intel's Itanium. For workstations, Microsoft offers the Windows XP 64-bit edition for the IA-64 (Itanium) architecture and the Windows XP x64 edition for AMD64 and Intel EM64T architectures. Windows Server 2003 Standard, Enterprise and Datacenter editions all come in 64-bit versions. Mac OS X "Tiger" can run 64-bit applications on PowerPC G5 64-bit systems, and the next version ("Leopard") is expected to be a full 64-bit OS.

Should you upgrade to 64-bit for best scalability?
To take full advantage of 64-bit technology, you need 64-bit applications -- and that's where the problem lies. While a number of software vendors in the business space provide native 64-bit server applications (some examples include Microsoft's 64-bit enabled SQL Server 2005, IBM's Tivoli Storage Manager, e-commerce software from Computer Associates and software from Oracle and SAP) -- and in fact, Microsoft made waves by announcing that Exchange 2007 would be 64-bit only -- there are far fewer desktop/consumer level applications available in 64-bit versions.

Should you upgrade now?
If this technology is out there, and the industry is moving towards a 64-bit takeover, does that mean you should buy only 64-bit computers as you add new systems or replace old ones? The answer is (as is so often the case): it depends.

One of the biggest problems with making the transition to 64-bit is finding the appropriate drivers for hardware peripherals. If you need to use older devices, you may want to think twice about making the move to 64-bit. On the other hand, if you need to run memory-intensive applications that will benefit from the larger memory space offered by 64-bit systems, spending the extra bucks to upgrade will probably pay off in the long run.

Your best strategy might be to go to 64-bit when you replace servers or install new ones, then upgrade to 64-bit for graphics and CAD workstations and the like. As for those workstations that are used for ordinary office productivity software, email, web and the like, you probably don't need the scalability of 64-bit anytime soon, so you can save money by sticking with 32-bit systems there.

One thing you can be sure of: if you do buy 64-bit hardware, you'll have more scalability. After all, even if you don't plan to upgrade your operating systems yet, you can always run 32-bit software on the 64-bit machines until you're ready to go to the new OS.

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