"one reason to use flash over ajax is flash is faster at rendering large amounts of data in a grid:" I'm a little confused about the point you're trying to mak

"one reason to use flash over ajax is flash is faster at rendering large amounts of data in a grid:" I'm a little confused about the point you're trying to make here, given that Ajax is a method for retrieving data from the server with Javascript. That has nothing to do with rendering that data to screen. Unless you mean the Flash version can preload all the data. This is a design decision and can be made in a HTML/JS grid as well. Regardless, this has nothing to do with HTML5 and the HTML5 spec itself has nothing to do with performance. Performance is implementation specific.