To continue from my previous post, here are some additional performance tools to know about.

First is a JavaScript memory analyzer that was just put out a short time ago. Read about it here: http://blogs.msdn.com/b/visualstudio/archive/2013/01/28/javascript-memory-analysis-for-windows-store-apps-in-visual-studio-2012.aspx

Second, here are topics in docs on performance analysis:

Analyzing performance of Windows Store Apps

Timing and Performance APIs (HTML/JS)

Analyzing memory usages in Windows Store Apps (HTML/JS)

Analyzing the code quality of Windows Store apps with Visual Studio code analysis (C#, VB, C++)

 

Finally, there are two posts on the Windows 8 Developer Blog that are relevant:

How to improve performance in your Metro style app

Tackling performance killers: common performance problems with Metro style apps