http://www.winsupersite.com/reviews/...64_preview.asp
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.
Linear Mode
