One of the biggest changes in the new A5X is the sheer size of the die. The A5X is 310% larger than the A4, the processor in the iPhone 4 and the original iPad. Each of the four GPU cores take up a huge chunk of the A5X, each GPU core is larger than the individual ARM cores of the CPU.
For fans of die photos, Chipworks is also offering a 1200px wide unmarked die photo of the A5X to be used as iPad wallpaper.
Update: Chipworks has updated their blog post with a iPad 3-ready 2056px wide shot of the A5X.