In addition to Windows XP Professional x64 Edition (see my preview), Microsoft is also prepping two x64-based Windows Server 2003 products, collectively known as Windows Server 2003 x64 Editions, for release. The Windows Server 2003 x64 Editions are comprised of Windows Server 2003 Standard x64 Edition and Windows Server 2003 x64 Enterprise Edition, which roughly correspond to the similarly named 32-bit versions of Windows Server 2003. However, because they are based on the 64-bit x64 platform, these product editions can access far more RAM than their 32-bit brethren, placing them somewhere between Microsoft's x86- and Itanium-based Windows Server versions.

From a functional standpoint, the Windows Server x64 Editions are based on the code for Windows Server 2003 Service Pack 1 (SP1, see my preview /reviews/win2003sp1_beta.asp) and not on the original shipping version of Windows Server 2003. That means that these products include new SP1 features, like the Security Configuration Wizard (SCW, Figure) and all of the new security and bug fixes that are found in 32-bit Windows Server 2003 SP1. But since the x64 Editions of Windows Server 2003 don't offer new features, per se, when compared to Windows Server 2003 with SP1, it doesn't make much sense to run through every single new feature here. Instead, in this preview, I'll call out the features that differentiate Windows Server 2003 x64 Editions from the 32-bit versions of Windows Server 2003 with SP1.

System requirements

Windows Server 2003 x64 Editions require server hardware that is based on the x64 platform. These servers feature AMD Opteron or Intel Xeon with EM64T or Intel Pentium 4 6xx series microprocessors. On the AMD side, Microsoft requires a 1.4 GHz or faster processor, while Intel users will need a 2.8 GHz Xeon or 3.2 GHz Pentium 4 with Hyper-Threading technology, or faster processor. However, Microsoft recommends faster Intel processors for the best experience: a 3.6 GHz Xeon or Pentium 4.

Performance

Microsoft doesn't want reviewers testing performance of these operating systems using pre-release code, which is fine because I don't typically run performance benchmarks anyway. (My testing was all performed with a single processor AMD-based system with a 2.2 GHz clock speed.) But the company tells me anecdotally that x64 has proven to be an amazing resilient architecture, offering full 32-bit application performance when running under a 64-bit operating system. This was a performance goal that eluded the company when working with the Itanium. "We wanted to eliminate any adoption barrier [for x64]," Iain McDonald, a Microsoft director of Windows Server program management, told me recently. "We think we nailed it."

But even for 32-bit applications, the x64 platform offers some advantages over x86 hardware. When you boot into a 64-bit Windows OS on x64 hardware, you get additional registers, and 32-bit applications each get a full 4 GB of address space, compared to 2 GB, typically, on a 32-bit box (previous 32-bit Windows client and server versions do support an optional 3 GB application address space mode).

Architectural improvements in the x64 chips, I'm told, also help with performance. The net effect is that 32-bit applications running in a 64-bit Windows version run at parity when compared to running in a 32-bit OS. In some cases, the code runs faster on x64, even dramatically faster. The reason, Microsoft says, is the additional resources a true x64 environment provides. The aforementioned application address space size is over 4,000 times larger than with x86 systems. The maximum physical memory is currently 8 times larger per server. The non-paged and pages memory pools are about 256 times larger on x64.

The nice thing about this performance boost is that it's not manufactured to meet a certain agenda. That is, Microsoft doesn't have to provide very specific benchmarks to prove its point. Instead, they've found Windows x64 to be faster running 32-bit code than 32-bit versions of Windows across the board. I'll provide the details when the final versions of the Windows Server 2003 x64 Editions ship.

The x64 Editions compared with 32-bit Windows Server 2003 versions

Now that the x64 Editions have been added to Windows Server 2003 lineup, here's how they compare with their stablemates:

Windows Server 2003 Edition Processors RAM Platform
Windows Server 2003 Web Edition 2 2 GB x86 (32-bit)
Windows Server 2003 Standard Edition 4 4 GB x86 (32-bit)
Windows Server 2003 Enterprise Edition Edition 8 32 GB x86 (32-bit)
Windows Server 2003 Datacenter Edition 32 64 GB x86 (32-bit)
Windows Server 2003 Standard x64 Edition 4 32 GB x64 (64-bit)
Windows Server 2003 Enterprise x64 Edition 8 1 TB x64 (64-bit)
Windows Server 2003 Datacenter x64 Edition 64 1 TB x64 (64-bit)
Windows Server 2003 Enterprise 64-Bit Edition 8 1 TB Itanium (64-bit)
Windows Server 2003 Datacenter 64-Bit Edition 64 1 TB Itanium (64-bit)

Who will want Windows Server 2003 x64?

As customers migrate from x86 to x64, they will inevitably begin taking advantage of the unique 64-bit features of x64. This transition will take time. In 2005, it's likely that most x64 servers will run a 32-bit Windows Server 2003 version, along with associated 32-bit drivers and applications. But once an x64 version of Windows Server is installed on such a system (with associated 64-bit drivers), you've opened up new possibilities. In addition to 32-bit applications and services, you can start exploring a new generation of 64-bit applications as well.

Key among these will be the upcoming x64 editions of the SQL Server 2005 database server, which will support large databases, including in-memory databases, that would be impossible on 32-bit systems. But Windows Server 2003 x64 Editions will also be uniquely suited for other 64-bit tasks, including serving 75 percent more Terminal Services clients per machine than is possible with 32-bit server hardware. Microsoft also sees benefits for Active Directory (especially with data stores larger than 2 GB), IIS 6.0 Web serving (where increased capacity will reduce cache recycling and improve performance), high performance computing clusters, and business applications such as ERP and CRM.

I'll look more closely at these applications in my eventual Windows Server 2003 SP1 and x64 Review, due in April 2005. But the future looks bright for x64 server hardware. "I don't want anyone on my team buying 32-bit servers any more because, frankly, in two years time, they're going to be doorstops," McDonald said.

Timing and delivery

Microsoft will finalize the Windows Server 2003 x64 Editions in late March and deliver the products in April. Like their 32-bit counterparts, the Windows Server 2003 x64 Editions will be sold with new server hardware. It's not clear at this time whether Microsoft intends to make the software available separately. My guess it will not do so.

Conclusions

For virtually every server application imaginable, x64 is the platform of the future, and one that all Windows Server administrators should be thinking about and, potentially, evaluating this year. As with XP x64, driver and application compatibility will likely bedevil many users this year, but the by the release of Longhorn Server (expected in early 2007), x64 will be the mainstream server platform. That schedule might be a bit conservative, actually. Because most of Microsoft's feature packs and other Window Server 2003 add-ons, and prominent server-based products, are already compatible with Windows Server 2003 x64 Editions, will be made compatible, or will soon be upgraded to full x64 versions themselves, there will soon be precious few reasons not to migrate to x64. More important, perhaps, the memory headroom on these systems are so great, that the Windows Server 2003 x64 Editions will probably find huge adoptions in the middle of the market above small businesses and below the largest enterprises that still need the scalability benefits of Itanium. That's a huge market, and one that x64 is uniquely positioned to conquer beginning this year. Windows Server 2003 x64 Editions are solid, offering a no-compromises upgrade path to 64-bit computing.