One of the more common questions I hear about Vista is which bit version of Windows Vista should one get. Do we go with x86 32 bit edition or x64 64 bit edition? I'm going to try to clear that question up as best as I can and explain the pros and cons of each choice.
First we must understand a little background on what x64 is. X64 is the 64 bit extension technology that AMD invented (AMD64) to seamlessly migrate the 32 bit x86 (as in 286, 386, 486 compatible microprocessors) world into a 64 bit era. Intel in partnership with HP had refused to extend the ancient x86 platform and had already committed to its all new pure 64 bit IA-64 Itanium architecture. While Itanium was fundamentally superior, its x86 emulation provided inferior performance for existing applications and the adoption rate was very slow. Intel had hoped that the market would leap to the new platform but there was no seamless way of making that migration, and Itanium failed to gain widespread adoption. AMD took the opportunity to extend the existing x86 architecture with 64 bit capability by handling 64 bit CPU registers and adding a lot more registers, and it was immediately greeted warmly by the market. In a reversal of roles, Intel found itself copying AMD64 (permitted by an AMD-Intel cross-licensing agreement) and calling it EM64T. The two x64 technologies are essentially identical except for a few minor differences in the implementation.
Microsoft initially created a version of Windows XP called XP 64 bit Edition, a pure 64 bit operating system that ran on IA-64 Itanium and only supported x86 applications through emulation. There was even a Windows 2000 Server version for IA-64 as well. The problem was that the adoption rate of IA-64 was very slow, and when AMD created AMD64--with Intel having no choice but to follow--Microsoft created the x64 edition of Windows XP as well as Windows Server 2003. The x64 editions were hybrid 32/64 bit operating systems that could natively run 32 or 64 bit code at full speeds without software emulation, whereas the 64 bit edition of Windows XP relied on software emulation to run existing x86 32 bit code. With the release of Vista, Microsoft simultaneously launched the 32 bit x86 and the 64 bit x64 editions. The retail editions contain both the x86 and x64 editions, while the OEM versions contain one or the other and you have to decide before you order. Now one of the most common questions people ask is whether to run 32 or 64 bit Vista.
The first thing you must do is to make sure your particular CPU supports x64. [Dave Leigh in the talkback posted this link to Steve Gibson's x64 detector which is a simple utility to check your hardware.] Here's a simplified summary of the situation:
- Almost all new servers sold within the last two years from AMD or Intel will have x64 capability.
- Most mid- to high-end desktop processors from AMD or Intel within the last year have x64 capability.
- Some higher-end Semprons have x64; lower-end Semprons do not.
- No AMD Durons have x64.
- All AMD Opteron processors have x64.
- All AMD X2, FX, and Athlon64 chips have x64.
- All Intel Pentium D and Celeron D chips have x64.
- All AMD Turion notebook processors have x64.
- All Intel Core 2 processors (mobile, desktop, and server) have x64.
- No Intel Core Duo notebook processors have x64
- No Intel Pentium M notebook processors have x64.
Drivers are the death of x64
The second thing you must check is to see if all your hardware has x64 Vista driver support, either included in the OS or downloadable from the hardware vendor. At this point, many motherboard makers have failed to include the latest 5.1 sound and network drivers, and you might have to look to the chipset maker for drivers. For example, you can find Realtek 32/64 bit drivers here for Gigabit LAN and 5.1 audio support. NVIDIA has the latest 32 bit and 64 bit drivers. ATI (AMD) has 32 and 64 bit drivers here. Creative has drivers here, but its x64 support is sorely lacking, and it's either missing or in beta. While these are the fundamental hardware drivers you'll need, the killer for Vista x64 edition is finding drivers for obscure hardware like cameras, printers, scanners, and other accessories.
You don't have to worry about 32 bit software compatibility in Windows Vista or XP x64, since they run natively and seamlessly, but drivers are an absolute killer. If you happen to find 32 bit drivers for your device but no 64 bit drivers, you're out of luck if you're running x64 Windows XP or Vista. For this reason, x64 edition for a typical consumer is usually not very practical because there are simply too many hardware peripherals you won't be able to use. Getting the computer itself to work is relatively easy; it's the one or two obscure devices that stops you dead in your tracks if you must have that device working. For this reason, no PC maker (that I'm aware of) will pre-load x64 edition of Windows on its PC because it will be a support nightmare if a customer starts complaining about a printer driver that won't load. To this date, Apple iTunes won't support any x64 edition of Windows, and it will absolutely not work at all because of hardware driver issues.
Servers, on the other hand, don't typically ever need to see peripheral devices, and they need to work with only the limited set of hardware they're sold with. Any self-respecting server hardware trying to sell you something like an HBA Fiber Channel adapter or iSCSI adapter will have to offer full x64 support. Microsoft Exchange Server 2007, for example, ONLY comes in x64 editions, and we're likely to see more software coming out like this to promote 64 bit. There is very little risk in standardizing on x64 edition in the data center since all legacy 32 bit applications will run natively at full speed.
Dedicated workstations for professionals are another great candidate for x64 edition so long as they're willing to put up with limited peripheral support. x64 allows high performance computing tasks to run extremely fast and efficiently. The free Paint.NET image editing application, for example, is fully optimized for multi-core and x64, yet Adobe can't get its act together and won't even release an x64 edition of the upcoming Photoshop CS3. That doesn't mean you can't run x86 Photoshop; in fact, it will still probably run a little better on Windows x64 because more than 4 GBs of RAM can be supported with ease, which gives more memory to Photoshop. It's just a crying shame for Adobe to lag behind, because Paint.NET has shown tremendous speed increases using x64 for filtering and layering effects on the order of 50 to 100 percent speed boosts. Adobe should have been supporting x64 two years ago and it won't even do it next year.
The bottom line is that you have to look at your own hardware limitations before you can make any kind of a transition. If all the hardware you want to use will work on Vista x64, it's well worth the transition.