The latest version of the WPF Performance Suite has just be released in the Windows SDK for Windows Server and .NET Framework 3.5! If you install the SDK, you'll find WpfPerf.msi, which lets you install the latest perf suite. The accompanying “Performance Profiling Tools for WPF” article has been updated to reflect the changes, but note that the MSDN version of the doc still reflects the previous version of the tool.
In addition to UI enhancements for usability, this version of the performance suite includes fixes to all previously known crashes. Please remember to remove all older versions of WPFPerf.exe before installing this version of the performance suite!
Also, you may want to read over the SDK download notes before installing the SDK. For example, it’s important to note that this SDK release is an ISO-only download.
Another valuable resource: Tim Cahill’s Profiling How-To’s.