All good points, azakai. Ashley: Given that you are running on Windows, unless you have manually enabled the desktop OpenGL option in Chrome, your WebGL calls

All good points, azakai. Ashley: Given that you are running on Windows, unless you have manually enabled the desktop OpenGL option in Chrome, your WebGL calls are running through the ANGLE layer. That means they are getting translated to native D3D under the hood. http://blog.chromium.org/2010/03/introducing-angle-project.html http://blog.chromium.org/2010/03/introducing-angle-project.h... A couple more possible explanations: 1) Your performance may be dominated by the overhead of lots of API calls. For example, drawing 4-vertex sprites individually would do that. ANGLE forwards those calls to a separate process for security reasons, but as a side effect you can end up with a whole core devoted to nothing but API overhead. This could actually run a lot faster than API + everything else on a single core. 2) The Transgaming guys working on ANGLE have a lot of experience auto-translating other people's crappy 3D code between OGL<->D3D. (http://transgaming.com/news/transgaming-developing-angle-project http://transgaming.com/news/transgaming-developing-angle-pro...) It's possible that their translation of your OpenGL is a better use of D3D than your own D3D.