We design Windows operating systems to perform well out of the box. However, many factors affect actual performance: firmware design, applications that load at system startup, memory and I/O components, and the built-in capabilities of system components such as graphics, storage, and networking devices.
To help system designers and manufacturers, we provide tools and information for the design and tuning of systems for best performance.
Windows Vista and Windows Server 2008 System Performance
Interrupt-Affinity Policy Tool
Windows Performance Tools Kit, v.4.1.1 (QFE) 
Measuring Performance in Windows Vista
Measuring System Resume Performance on Windows Vista
On/Off Transition Performance Analyzer 
Performance Tuning Guidelines for Windows Server 2008 
Windows PC Accelerators: Performance Technology for Windows Vista
Windows Server Performance Team Blog
Performance and Assessment – WinHEC 2006
Hybrid Hard Disk & ReadyDrive™ Technology: Improving Performance and Power for Windows Vista Mobile PCs [WinHEC 2006; 968 KB]
Windows Vista Performance Technologies [WinHEC 2006; 439 KB]
Windows Vista System Requirements and WinSAT [WinHEC 2006; 460 KB]
LINK: http://www.microsoft.com/whdc/system/sysperf/default.mspx
