The problem is that many current Android apps won't initially take advantage of the 64-bit processor until they're updated. Some of Google's native apps, including Chrome, Gmail, Calendar and Google Play Music do utilize the 64-bit CPU, and any "pure Java language" Android apps will run as 64-bit apps automatically, according to Google. It could be some time before the bulk of quality Android apps are updated for the new processor, though.
4) Nexus 9 Has NFC, Kindle Fire HDX 8.9 Doesn't
The Nexus 9 has NFC, while the Kindle Fire HDX does not. That means you can use the Nexus 9 along with Google Wallet, or another compatible mobile payments apps, to pay for goods and services in many establishments where contact-less payments are accepted. (Of course, I'm not exactly sure why you'd want to use your tablet instead of your phone to make a mobile payment...unless your phone doesn't have NFC.)
NFC isn't exactly widely used today, but thanks to Apple's adoption of the technology in the latest iPhones, and the success of its Apple Pay service, NFC is finally in the limelight.
NFC is not all about payments. For example, you can use NFC tags to trigger certain features or functions on your mobile device. You can use NFC to print from your phone or tablet. Some organizations use NFC for user authentication and building access, as well. Nexus 9 users could potentially employ their tablets for some or all of these purposes. Kindle Fire HDX owners are out of luck when it comes to NFC.
5) Nexus 9, Google Play Store and Apps, Apps and More Apps
Today more than ever, software defines the true value of a computing device. That's why I listed the dramatic difference in user experience between the Nexus 9 Android OS and Kindle Fire OS as the first point in this post. There's another component to the "pure" Android versus Amazon Fire OS argument, though: apps.
Both Google and Amazon operate their own app stores, the Play Store and the Amazon App Store for Android, respectively. Google had 1.3 million apps available in the Play Store in July 2014, according to Statista. Amazon had about 240,000.
Then there's the fact that you can easily install the Amazon App Store for Android on you Nexus tablet. You simply need to check a security option that lets you install apps from "unknown sources." You can't install Google Play or any native Google apps, without rooting your Kindle Fire HDX. (That's fine if you like to tinker with your devices, but something tells me that the average Amazon tablet user probably isn't a tinkerer. Even if you do root your Fire tablet, the process for "sideloading" apps, and keeping them updated, is tedious to say the least.)
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