Nokia Lumia 830 GSM Smartphone, Black - AT&T - No Warranty This phone works only with the AT&T network and comes with a pre-installed nano SIM card. Internal Memory: 16 GB, 1 GB RAM AT&T retail sealed Packaging phone color is gray with an optional green back door included. CPU: Quad-core 1.2 GHz Cortex-A7 GPS: Yes, with A-GPS, GLONASS, Beidou. Display: 720 x 1280 pixels, 5.0 inches (~294 ppi pixel density).