| ViewSonic ViewPad 4 | HTC HD2 |
| Manufacture | ViewSonic | HTC |
| Model | ViewPad 4 | HD2 |
| Form factor | Block | Block |
| Weight | NA | 157.00 |
| Dimensions (HxWxD) | 121 x 66 x 11 | 121.00 x 67.00 x 11.00 |
| Operating System | Android | Windows Mobile |
| Networks | 2G - 800/850/1800/1900 3G - 900/2100 | 2G - 850/900/1800/1900 3G - 900/2100 |
| HSCSD |  | |
| GPRS |  | |
| EDGE | | |
| UMTS | | |
| HSDPA | | |
| HSPA+ | | |
| WiMAX | | |
| LTE (4G light) | | |
| WLAN / Wi-Fi | | |
| Wi-Fi Hotspot | | |
| Wi-Fi Direct | | |
| SMS | | |
| MMS | | |
| | |
| HDMI out | | |
| USB port | | |
| MHL | | |
| Bluetooth | | |
| Bluetooth version | NA | NA |
| DLNA | | |
| GPS | | |
| Glonass | | |
| ANT+ | | |
| IrDA | | |
| NFC | | |
| 3.5 mm audio connector | | |
| Camera | | |
| Camera resolution | 5 megapixel, autofocus | 5 megapixels, autofocus |
| Image Stabilization | | |
| BSI sensor | | |
| Camera Flash/Light | | |
| Flash type | NA | NA |
| Video recording | | |
| Video capture resolution | NA | NA |
| Second Camera | VGA (640 x 480) | NA |
| Display size | 4.1 inches | 4.30 |
| Touchscreen | | |
| Colour display | | |
| Number of colours | 16000000 | 65000 |
| Display width | 480 | 480 |
| Display height | 800 | 800 |
| PPI | 227.55 | 216.97 |
| Second Display | NA | NA |
| CPU | 1 GHz Qualcomm MSM 8255 | 1 GHz Snapdragon |
| GPU | NA | NA |
| Memory | 512 MB | 448 MB. Expandable with microSD card |
| Micro SIM | | |
| Dual SIM | | |
| MP3 | | |
| Ringtones / Music file format | MP3 | MP3, AMR, MP4, M4A, AAC, WMA, WAV, QCP, MID |
| Java | | |
| Games | Yes | NA |
| FM Radio | | |
| Battery | NA | 1230 mAh |
| Standby time (h) | NA | 490 |
| Talktime (m) | NA | 380 |
| Wireless Charging | | |
| Browser | Android HTML Webkit | Opera Mobile |
| Calendar | | |
| Voicedialing | | |
| IP Code | NA | NA |
| Predictive text | | |
| RSS reader | | |
| Voicememo | | |
| PC Synchronization | NA | |
| SyncML | | |
| Website | Website | Website |