use -webkit-transform: translate3d(0, 0, 0) in style.mobile.css for better performance on iOS, and to prevent tile blinking effects on iOS 5

theme/default/style.mobile.css

@@ -49,3 +49,15 @@ div.olControlZoom a:hover {
     -o-transition: opacity 0.2s linear;
     transition: opacity 0.2s linear;
 }
+/* Enable 3d acceleration when operating on tiles, this is
+   known to yield better performance on IOS Safari.
+   http://osgeo-org.1803224.n2.nabble.com/Harware-accelerated-CSS3-animations-for-iOS-td6255560.html
+
+   It also prevents tile blinking effects in iOS 5.
+   See https://github.com/openlayers/openlayers/issues/511
+*/
+@media (-webkit-transform-3d) {
+img.olTileImage {
+    -webkit-transform: translate3d(0, 0, 0);
+}
+}