Big performance difference between WinForms and Wpf examples

Question

I notice a very important performance difference (in FPS) between the CefSharp.WinForms.Example and CefSharp.Wpf.Example when using http://www.vsynctester.com

When turning off VSync in my video card control panel and in the settings in CefExample Init()

settings.CefCommandLineArgs.Add("disable-gpu-vsync", "0");

For CefSharp.WinForms.Example I get around 500 FPS (steady) For CefSharp.Wpf.Example I barely get 30 FPS

I understand that Wpf uses offscreen rendering, but what explains the big performance difference for the same web page?

I'm using a MacBook Pro with Win 8.1 with NVidia GT 750M Graphics. CefSharp version is 8755a9496ffbd5f21bc6ef062bce687a22d83938 (March 1st 2015) and Cef version 3.2171.1979

Answer 1

The maximum rate in frames per second (fps) that CefRenderHandler::OnPaint will be called for a windowless browser. The actual fps may be lower if the browser cannot generate frames at the requested rate. The minimum value is 1 and the maximum value is 60 (default 30).

Direct quote from the CEF documentation see http://magpcss.org/ceforum/apidocs3/projects/%28default%29/_cef_browser_settings_t.html#windowless_frame_rate

The entire process is more CPU bound that it is GPU bound. The slow part is the bitmap buffer is copied in memory, before it's displayed. CEF also supports DirtyRects which is currently not implemented, so even a small graphical change forces a complete screen redraw.

When the upstream CEF issue 1006 is resolved we can then look at making some more improvements. https://code.google.com/p/chromiumembedded/issues/detail?id=1006&q=label%3AOSR