loads.in gives you the possibility to see how fast your (or any) website loads in a real browser from over 50 locations worldwide.

Here are some MySQL optimization techniques for programmers. from nettuts+.

an easy gzipping win.

from lifehacker.

If you're not using PHP's output buffering, you should be. And if you are, you may not be using it to its potential.

dynamically loading JavaScript files allows your page to render faster and therefore improve perceived performance.

css amalgamation, whitespace removal, caching. from nettuts+.

a Xdebug profiling web frontend in PHP5.

Xdebug's Profiler is a powerful tool that gives you the ability to analyze your PHP code and determine bottlenecks or generally see which parts of your code are slow and could use a speed boost.

Following a handful of best practices in database design will improve speed and efficiency for most web applications.

Page Speed is an open-source Firefox/Firebug Add-on. Webmasters and web developers can use Page Speed to evaluate the performance of their web pages and to get suggestions on how to improve them. From Google Code.

how to analyze and optimize your database.

negative impact on web page performance.

setting the record straight.

when dealing with files with static content.

image format specific non-lossy image optimization tools.

more responsive, cleaner, and more optimized.

34 best practices divided into 7 categories. from yahoo! developer network.

using javascript to implement advanced css. from eric meyer.

mvc framework that is orm-agnostic, javascript library agnostic, and template language agnostic.

data output, loops, variables and functions, etc.

performance improvements for dom manipulation.

page weight and load time. practical implementation of the proxy design pattern.