HTML5 And CSS Performance
HTML/CSS Composite Score
We're combining the HTML and CSS performance scores into a single rendering composite. This lowers the number of performance-oriented categories counted in our final score. Besides, nearly all modern Web pages utilize CSS alongside HTML for layout, making the two practicaly inseparable for rendering.
Chrome takes the lead in HTML and CSS rendering under both operating systems, with a slight advantage in Windows 8. Firefox earns identical second-place scores for both versions of Windows. Mozilla is followed closely by Microsoft Internet Explorer 10 on Windows 8, which is quite a ways ahead of IE9 on Windows 7. Opera takes last place on both operating systems, achieving less than half of Chrome's winning scores.
IE10 takes the lead in HTML5 performance on Windows 8, followed by Chrome 23 and Firefox 16. In Windows 7, Chrome is the first-place finisher, followed by Firefox and IE9. Opera finishes last on both OSes.
The charts below contain the individual HTML5 performance benchmark results. A single GUIMark HTML5 score, which is included in our HTML5 composite score, is derived from the geometric mean of the four GUIMark2 HTML5 tests.
CSS (Cascading Style Sheets)
We're bringing back the Microsoft Maze Solver CSS test. It was originally removed because it exposes a bug in Firefox that makes Mozilla's browser score extremely low. Unfortunately, the replacement CSS tests are doing the opposite, giving Firefox implausibly-high scores. By running these tests together, we hope to balance out both extremes. No other browser suffers these oddities in either CSS test.
Our CSS composite score uses four test sites: CSS Speed Test, CSS3 Speed Test, CSS Stress Test & Performance Profiling, and Maze Solver. To quickly recap, we run the CSS Stress Test and Performance Profiling bookmarklet on both the CSS and CSS3 versions of the CSS Speed Test demo page. We then average those two results and create a geometric mean using that score and the results from Microsoft Maze Solver.
Google Chrome takes the lead, earning first place on both versions of Windows. Firefox places second under both OSes, followed by Internet Explorer and Opera. All of the browsers again demonstrate better performance under the new version of Windows.
The charts below contain the results for the individual CSS and CSS3 Speed tests, as well as the combined CSS2.1/CSS3 Maze Solver test.
IE9 finishes faster on Windows 7 than IE10 on Windows 8 in the CSS test and Maze Solver. Meanwhile, Opera 12.10 displays an advantage on Windows 8 in the CSS3 test. In order to avoid heavily skewing our final scoring, we have to add a whole second to the average CSS Speed Test results to remove the zero-sum score.