Nokia Lumia 635 vs Nokia Lumia 620
| Type | Touch | Touch |
| Dimensions | 129.50 x 66.70 x 9.20 mm | 115.40 x 61.10 x 11.00 mm |
| Weight | 134.00 g | 127.00 g |
| Display size | 4.50" | 3.80" |
| Display | Color / IPS TFT 16M colors 480 x 854 px (4.50") 218 ppi | Color / IPS TFT 16M colors 480 x 800 px (3.80") 246 ppi |
| Display protection | Corning Gorilla Glass Buy screen protector
 |  |
| Additional display | | |
| Protection of the secondary display | | |
| Talk time (max.) | 2G: 720 min. (12.0 h) 3G: 840 min. (14.0 h) | 2G: 876 min. (14.6 h) 3G: 594 min. (9.9 h) |
| Stand-by (max.) | 3G: 648 h. (27.0 days) | 3G: 330 h. (13.8 days) |
| Playback time (max.) | Audio: 58 h (2.4 days) Video: 7 h (0.3 days) | nd |
| Internet browsing time (max.) | WiFi: 9,4 h (0.4 days) 3G: 8,8 h (0.3 days) | nd |
| Standard battery | Li-Ion 1830 mAhBuy powerbank
| Li-Ion 1300 mAhBuy powerbank
|
| Quick battery charging | | |
| Wireless battery charging | | |
| Internal memory | 8 GB | 8 GB |
| RAM memory | 512 MB, 1 GB | 512 MB |
| Memory cards |  microSD, microSDHC, microSDXC up to 128 GBBuy memory card | microSD, microSDHC, microSDXC up to 64 GBBuy memory card |
| Operating system | MS Windows Phone 8.1 | MS Windows Phone 8 |
| Processor | Qualcomm Snapdragon 400 | Qualcomm MSM8227 |
| Processor clock | 1200 MHz | 1000 MHz |
| GPU | Adreno 305 | Adreno 305 |
| Touchscreen | | |
| DualSIM | | |
| SIM cards standard | SingleSIM(microSIM) |  |
| Other names | - | - |
| GSM frequencies | 850 900 1800 1900 | 850 900 1800 1900 |
| UMTS | 850 900 2100 | 850 900 1900 2100 |
| LTE standard | FDD LTE: 2600, 1800, 800 | |
| CDMA | | |
| Standard TD-SCDMA | | |
| UMA | | |
CAMERAS - BACK
| First camera | | |
| Photo matrix | 5 Mpx | 5 Mpx |
| Resolution | 2592x1944 px | 2592x1936 px |
| Optical zoom | | |
| Digital zoom | 4x | 4x |
| Flash | | LED |
| Dual-colour LED flash | | |
| Video resolution | 1280x720 px | 1280x720 px |
| Video formats | H.264, MPEG4 | H.264 - 30 fps |
| Additional | AF, f/2.4 | - |
CAMERAS - FRONT
| First camera | | |
| Photo matrix | nd | 0.3 Mpx |
| Resolution | nd | 640x480 px |
| Optical zoom | nd | |
| Flash | nd | |
| Dual-colour LED flash | nd | |
| Video formats | nd | H.264 - 30 fps |
| Additional | nd | - |
SENSORS
| Accelerometer | | |
| Proximity | | |
| Light | | |
| Magnetometer | | |
| Gyroscope | | |
| Barometer | | |
| Altimeter | | |
| Gravity | | |
| Hall-effect | | |
| Iris scanner | | |
| Fingerprint scanner | | |
| Thermometer | | |
| Hygrometer | | |
Data transfer
| xHTML | | |
| WAP | v2.0 | v2.0 |
| HSCSD | | |
| HSDPA | 42.20 Mbit/s | 21.00 Mbit/s |
| HSUPA | 5.76 Mbit/s | 5.76 Mbit/s |
| HSPA | | |
| HSPA+ | | |
| LTE DL | 102.00 Mbit/s | |
| LTE UP | 51.00 Mbit/s | |
| WIMAX+ | | |
| GPRS | | class 12 |
| EDGE | | class 12 |
| Bluetooth | v4.0 | v3.0 |
| A2DP Profile | | |
| HDMI | | |
| WiFi | v802.11 b/g/n | v802.11 a/b/g/n |
| WiFi frequencies | 2,4 GHz | 2,4 GHz |
| WiFi Direct | | |
| WiFi Display | | |
| DLNA | | |
| Miracast | | |
| WiFi hotspot | | |
| IrDA | | |
| USB | v2.0 | v2.0 |
| GPS | | |
| A-GPS | | |
| GLONASS | | |
| Beidou | | |
| NFC | | |
COMMUNICATION AND MESSAGING
| Call waiting | | |
| Conferency | | |
| Call forwarding | | |
| Push To Talk | | |
| Instant Messenger | | |
| SMS | | |
| EMS | | |
| MMS | | |
| Dictionary | | T9 |
| Swype | | |
| e-mail client | POP3, IMAP4, SMTP | POP3, IMAP4, SMTP |
| Hardware QWERTY keyboard | | |
| RSS Reader | | |
Multimedia
| Radio | | |
| MP3 | | |
| Stereo speakers | | |
| Audio Jack | 3.5 mm | 3.5 mm |
| HD Voice | | |
| Sound formats | AAC, AMR, ASF, M4A, WMA | AAC, AAC+, AMR, WAV, WMA, eAAC+ |
| Polyphony | | |
| Video ringtone | | |
| Ring composer | | |
| Games | | |
| Java | | |
| Videophone | | |
| DVB-H television | | |
| TV-Out | | |
PIM AND ADDITIONAL FUNCTIONS
| Watch | | |
| Stopwatch | | |
| Alarm | | |
| Calculator | | |
| Currency converter | | |
| Organizer | | |
| Calendar | | |
| Flight mode | | |
| SyncML | | |
| Data and fax | | |
| Screensaver | | |
| Themes | | |
| Interchangeable covers | | |
| Voice dial | | |
| Speakerphone | | |
| Recorder | | |
| Vibrations | | |