In 2.0.2 the following scene renders on my PC at 11fps
In 2.1b7 the following scene renders on my PC at 3fps.

http://www.zynaps.com/site/experiments/environment.html?mesh=bart.wft

TestApp
import javafx.application.Application;
import javafx.scene.Scene;
import javafx.scene.web.WebView;
import javafx.stage.Stage;

public class WebViewBart extends Application {
  public static void main(String[] args) throws Exception { launch(args); }
  public void start(final Stage stage) throws Exception {
    WebView webView = new WebView(); webView.getEngine().load("http://www.zynaps.com/site/experiments/environment.html?mesh=bart.wft");
    stage.setScene(new Scene(webView, 800, 800)); stage.show();
    System.getProperties().list(System.out);
  }
}