The Kindle Fire HDX comes in a 7-inch and 8.9-inch model and both feature what Amazon is calling HDX display, which is beyond high-definition. The 7-inch model has a 1,920 x 1,200 pixel resolution with a density of 323 pixels per inch, while the 8.9-inch model has 2,560 x 1,600 pixel resolution at 339 ppi — higher than Apple’s iPad. Amazon says a new feature dynamically adjusts the color and brightness of each pixel by using a unique algorithm. These are powerhouse tablets. They added the latest graphics engine, doubled the memory, and tripled the processing power with the most advanced 2.2 GHz quad-core processor. HDX displays bring together exceptional pixel density (up to 339 ppi), perfect 100% sRGB color accuracy, improved brightness, and dynamic image contrast. You also get up to 11 hours of battery life—17 hours when you’re reading. Even the largest new Kindle Fire—the 8.9″—is startlingly light. They re-imagined the design from scratch, with a new magnesium unibody and molded glass-nylon alloy. At just 13.2 ounces, it’s 34% lighter than the previous generation. Kindle Fire HDX is packed with hundreds of updates, including new email, calendar, and productivity apps, X-Ray for Music, Second Screen, and—in addition to streaming—you can now download Prime Instant Videos and watch them offline.