http://weblogs.java.net/blog/chet/archive/2003/09/volatileimage_q.html
Volatile Images are an attempt to keep the image in your video card's memory.
With improvements in BufferedImage (so-called managed images) don't
assume you have to go Volatile to get the most out of your hardware.
Also, be sure you're using the latest version of Java (Java Se 6). They
keep tweaking and improving the speed of the Java2D and Swing.