The Lumia 640 has a 5-inch HD (1280×720) IPS LCD display while the Lumia 640 XL has a 5.7-inch IPS LCD display. Both come with Corning Gorilla Glass 3. The Lumia 640 has an 8-megapixel camera while the Lumia 640 XL has a 13-megapixel camera and Carl Zeiss optics. Both are powered by 1.2 GHz quad-core Qualcomm Snapdragon processor, 1GB of RAM, and have 8GB of internal storage that can be further expanded with up to 128GB with a microSD card (plus 30GB of free OneDrive online storage). Both also offer long lasting battery and fast LTE connectivity. The Lumia 640 and Lumia 640 XL will come with the Windows Phone 8.1 and the Lumia Denim update and will be upgradable to Windows 10 when it becomes available later this year.
UPDATE: AT&T will carry the Lumia 640 and Lumia 640 XL, while T-Mobile and MetroPCS will carry the Lumia 640.
For more information on the Lumia 640 and Lumia 640 XL, check out this blog post from Stephen Elop – Executive Vice President of the Microsoft Devices Group. Stephen also talks a little more about Windows 10 and Lumia phones and delivering devices at the flagship level later this year.