It's important to know what is being measured and what is not. Basically Stella is timing the backend performance and network speed from a single server in a s

It's important to know what is being measured and what is not. Basically Stella is timing the backend performance and network speed from a single server in a single location. Since 80% of performance is front-end, I find it's often more interesting to look at rendering time instead. Most websites can get the html back to you in a few hundred milliseconds. The more interesting question is how long it will take the browser to download and render the associated resources. This is the pain your visitors will be feeling and probably the one you should focus on. Instead of trying to get your server response down from 500ms to 200ms, focus on getting your onload time down from 5 seconds to 2. One great open-source tool for measuring front-end performance is http://www.webpagetest.org/ http://www.webpagetest.org/. It allows you to test sites from various locations around the world in and it gives you detailed performance data, waterfall graphs and even videos of the page loading. One downside is that it is IE only but it does support IE6-IE9. Here is a sample report for Adioso on a DSL connection in Dallas in IE7: http://www.webpagetest.org/result/110111_ZF_27134dc481325cfa01368decbc94158a/ http://www.webpagetest.org/result/110111_ZF_27134dc481325cfa... As a disclosure, I'm the founder of a web performance company and sponsor the Ireland instance for WebPageTest although I have no financial benefit from promoting them.