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Why 64-bit is so important

David Coursey AnchorDesk

Published: 29 Sep 2003 15:45 BST

With AMD announcing its Athlon 64 processor, 64-bit computing was suddenly big news last week. But big news for whom, exactly? Should you care about 64-bit architecture? And what makes 64-bit processors so special, anyway? Those are some of the questions I want to answer today.

What exactly was announced last week?
AMD announced a new 64-bit processor, the Athlon 64, intended for desktop and mobile computers. It's backward-compatible with 32-bit operating systems (like Windows XP) and will also support a forthcoming 64-bit version of Windows XP (see below). AMD says the new processor will be price-competitive with 32-bit systems, making it a no-brainer to purchase. A couple of PC vendors have Athlon 64 hardware available now, with more on the way.

Why 64 bits?
I've talked to executives from AMD, Intel, Microsoft, and Apple, and all agree that 64-bit processors matter for two reasons: memory and processing power. Today's 32-bit chips work with 32 bits of data at a time and can address up to 4GB of memory; Intel's Itanium 64-bit processor, by contrast, works with 64 bits of data at a time and can address up to 16 terabytes of memory. The new processors should dramatically increase processing speed for complex math and graphics applications; Apple says its G5 64-bit systems can compute equations that once took days in a matter of minutes.

The processor isn't the only player here; the operating system and applications must be tweaked to take advantage of the additional power, too. For example, Intel introduced the 32-bit 80386 processor in 1985, but Microsoft didn't ship a fully 32-bit operating system -- Windows XP -- until 15 years later. It won't take nearly that long for us to move to 64-bit OSes; MS already has a 64-bit version of desktop Windows (dubbed Windows XP 64-Bit Edition for 64-Bit Extended Systems) in beta, as well as a 64-bit version of Windows Server 2003. Final release is expected early next year. There is talk of some game vendors releasing 64-bit beta versions of some titles in time for holiday shopping. Note that 64-bit OSes are already common in the Unix/Linux world.

OK, but I don't use 4GB of memory now or process complex equations. Why should I care about 64-bit chips?
If all you do is run Microsoft Office, you probably aren't bumping up against any of the limits of 32-bit processors. But if you're running scientific or graphics apps on a workstation, or if you're a gamer, the improved graphics capabilities should interest you. While I focus on desktop computing, you should note that 64-bit servers are already in use and should become much more common as businesses need to cross the 4GB memory threshold.