title: Do ExtJS charts perform better than FusionCharts?
body: <p>We're thinking about replacing FusionCharts with ExtJS charts in our application, since:</p>
  
  <ol>
  <li>We already use ExtJS for our entire UI. It would be nice to remove the overhead and expense of another commercial third-party dependency and API.</li>
  <li>We'd like to be able to display these charts on Flash-less mobile devices.</li>
  <li>It's much harder to extend and manage FusionCharts' Flash components than normal DOM objects.</li>
  <li>A few particular pages of our app are chock full of charts (on the order of hundreds of spark-like charts), and Flash is devouring memory like it's going out of style.</li>
  </ol>
  
  <p>I've looked at FusionCharts's JavaScript fallback, and it's just not aesthetically sufficient. Plus, I don't want a JavaScript implementation that's a "fallback".</p>
  
  <p>We're currently on ExtJS 3.2.0. Upgrading to 4.x is out of the question for the short term, but we could potentially sandbox Ext 4 to use just its charting if we deem it worth the effort.</p>
  
  <p>So my question is essentially <strong>does ExtJS 4's JavaScript charting perform significantly better than FusionCharts Flash charting?</strong> I'm mostly concerned with memory usage, secondarily with render time.</p>
  
  <hr>
  
  <p>I see <a href="https://stackoverflow.com/questions/6910681/stock-chart-in-extjs-4">this Stack Overflow question</a> indicating that, at least as of August 2011, Ext charts weren't really up to snuff. I know Sencha was concentrating on improving stability and performance in 4.1. Does anyone know if it's gotten better since then?</p>