The 64-Bit Balancing Act

Windows Vista is the second generation of Microsoft Windows operating systems designed to work natively with x64 architecture processors from AMD and Intel. While Microsoft’s first attempt in this area — Windows XP Professional X64 Edition — failed to gain much traction, the technology is maturing, and businesses considering a migration to Vista are taking a hard look at whether to deploy x64 editions of Vista instead of x86 editions. We’ll help you weigh the pros and cons of moving to 64-bit as you plan your upgrade from XP to Vista.

Pros of 64-bit

First, some no-brainer advice: If you’re planning to purchase new computers, regardless of whether or not you’ll have 32- or 64-bit Vista installed on them, buy systems that use the x64 architecture. That way you have a choice — both x86 and x64 versions of Vista can run on x64 hardware. More important, by buying x64 systems you’ll be future-proofing your hardware purchases because the future is going to be 64-bit. Microsoft has already announced that Windows Server 2008 will be the last server version of Windows that will be released in 32-bit flavors, and my guess is that client versions of Windows won’t be far behind.

Now let’s look at the hard questions:

What about driver support for devices? This was a big issue back when Windows XP x64 was released. But today there’s mostly good news in this area because device manufacturers now usually provide both 32- and 64-bit drivers, and they generally work without a hitch.

What about applications? Can you run your mission-critical 32-bit line-of-business applications on 64-bit Vista? No problem! When you install a native 64-bit application on Vista x64, it’s installed in the C:\Program Files folder on your hard drive. When you install a 32-bit app, however, it’s installed into a different folder, C:\Program Files (x86). It makes sense to isolate 64- from 32-bit apps like this because they run differently — Vista x64 uses something called a Windows-on-Windows emulator (WOW64) that simulates an x86 environment so that 32-bit applications can seamlessly run on x64 systems.

What are some other advantages of going 64-bit? First, while 32-bit Vista is limited to 4 gigabytes of RAM for all editions, with 64-bit you can go far beyond this limit — up to 8GB of memory on Basic, 16GB on Home Premium, and 128GB on Business, Enterprise and Ultimate editions.

More memory equals better performance and the ability to run more applications simultaneously. A quad-core processor with 8GB of RAM running Vista Ultimate absolutely screams. You’ll never whine that Vista is slow as a hog if you run a 64-bit edition on premium hardware. And if you’re a digital-content creator, work with CAD/CAM software or just consider yourself a power user, breaking through that 4GB ceiling into the rarified world of large memory is something you’ll never look back on with regret.

Enhanced security is another bonus if you’re running Vista x64. There are three additional security features on this platform that aren’t present on x86 versions: support for hardware-based Data Execution Prevention (DEP), which blocks unwanted code from executing when it overruns the memory; PatchGuard, which blocks unauthorized programs from extending or replacing portions of the Windows kernel; and a requirement that all 64-bit kernel-mode drivers must be digitally signed.

Cons of 64-bit

So what’s the downside of moving to 64-bit Vista? Well, first off, if your existing hardware is x86 then you have a choice — recycle it and buy new x64 hardware so you can deploy 32-bit Vista, or keep it and stick with Vista x86 instead. In other words, while you can install both 32- and 64-bit versions of Vista on x64 hardware, you can only install 32-bit Vista on x86 machines.

Second, even if you have 32-bit Windows XP installed on an x64 system, you can’t perform an in-place upgrade from 32-bit XP to 64-bit Vista — you must first save your files and settings, wipe the machine, install Vista x64, and restore your files and settings using Windows Easy Transfer or the User State Migration Tool (USMT). In fact, even if you’re the lucky owner of an x64 computer that has Windows XP X64 Edition installed on it, you can’t perform an in-place upgrade to 64-bit Vista — you have to wipe and reinstall.

Hardware and deployment issues aside, are there any other negatives of using 64-bit Vista?

For one thing, you won’t be able to run those trusty 16-bit business applications any longer — you know, the ones your business has been relying on for the past 100 years or so? That’s right, 16-bit applications won’t run on Vista x64. In fact, they won’t even install.

Maybe that doesn’t seem like a big issue if your company is a cutting-edge dot-something Web 2.x startup, but if you’re a bricks-and-mortar manufacturer or a conservative financial institution, those old 16-bit apps may be your business’s lifeblood. A bank I use just upgraded from MS-DOS to Windows 2000 only a few years ago, and I know a couple of companies that still use Windows for Workgroups on the shop floor.

But let’s get back to hardware issues and look at notebooks. Say you’ve got a notebook with an x64 processor; you install Vista x64 Business Edition on it, and everything works fine. You upgrade your RAM from 2GB to 8GB, and behold, Vista says it can see only 3.25GB of RAM. What’s wrong? Your processor could use the additional RAM, but your notebook’s chip set won’t support it. Your x64 notebook needs a Santa Rosa chip set before it will recognize more than 4GB of RAM, and these notebooks are just now becoming available. So while you can buy a desktop computer that has 8GB or 16GB of RAM pretty easily today, an 8GB notebooks is still rare — and expensive, as well.

Finally, although most 32-bit applications will run on 64-bit Vista, a few won’t, especially older applications and web apps that run within a web browser. An example is Adobe Flash Player, which currently isn’t supported for playback in a 64-bit web browser. To mitigate this and similar application compatibility issues, Microsoft includes both 32- and 64-bit versions of Internet Explorer in 64-bit Vista, with the 32-bit version of Explorer linked to the Start menu shortcuts by default. Still, something like this can be a hassle.

And what about native 64-bit applications for Windows? There aren’t many yet, but the day will come. Still, some manufacturers may take a few years to recode their software from scratch as native 64-bit apps. Your job is to weigh the costs against the benefits and decide.