It looks like Asus decided to give their highest end flagship smartphone an upgrade right before they launch it to the public. Originally, the Asus Zenfone 3 Deluxe was slated to receive a Qualcomm Snapdragon 820 at its core, but Asus just announced it will come with the slightly update Snapdragon 821 instead (at least for the 256GB version).
The rest of the models will of the phone will come with the Snapdragon 820, but Asus decided to go all out for the larger storage model to make it even more "premium." It will come later in the year with a premium price of $780 too, while the smaller versions will arrive next month in Hong Kong and Taiwan.