Product
Vivo Y91i
Vivo Y91i
Samsung Z4
Samsung Z4
Battery
Type 4030 mAh, non-removable Li-Ion 2050 mAh, removable
Body
Dimensions 155.1 x 75.1 x 8.3 mm (6.11 x 2.96 x 0.33 in) 132.9 x 69.2 x 10.3 mm (5.23 x 2.72 x 0.41 in)
SIM Nano-SIM + Nano-SIM Single SIM (Micro-SIM) or Hybrid Dual SIM (Micro-SIM, dual stand-by)
Weight 163.5 g (5.78 oz) 143 g (5.04 oz)
Comms
Bluetooth 4.2, A2DP, LE 4.0, A2DP, LE
NFC No No
Positioning GPS, GLONASS, BDS GPS, GLONASS
Radio FM radio FM radio
USB microUSB 2.0, OTG microUSB 2.0, OTG
WLAN Wi-Fi 802.11 b/g/n, Wi-Fi Direct Wi-Fi 802.11 b/g/n, Wi-Fi Direct
Display
Resolution 720 x 1520 pixels, 19:9 ratio (~271 ppi density) 480 x 800 pixels, 5:3 ratio (~207 ppi density)
Size 6.2 inches, 95.9 cm2 (~82.4% screen-to-body ratio) 4.5 inches, 57.6 cm2 (~62.7% screen-to-body ratio)
Type IPS LCD IPS LCD
Features
Sensors Fingerprint (rear-mounted), accelerometer, proximity, compass Accelerometer, proximity
Launch
Announced 2018, November. Released 2018, November 2017, May. Released 2017, June
Status Discontinued Discontinued
Main Camera
Dual 13 MP, f/2.2, PDAF 2 MP, f/2.4, (depth) -
Features LED flash, panorama Dual-LED flash, panorama, HDR
Single - 5 MP, f/2.2
Video 1080p@30fps 720p@30fps
Memory
Card slot microSDXC microSDXC (uses shared SIM slot)
Internal 16GB 2GB RAM 8GB 1GB RAM
  eMMC 5.1 -
Misc
Colors Starry Black, Ocean Blue, Red Black, Gold
Models - SM-Z400F, SM-Z400Y
Network
2G bands GSM 850 / 900 / 1800 / 1900 GSM 850 / 900 / 1800 / 1900 - SIM 1 & SIM 2 (dual-SIM model only)
3G bands HSDPA 850 / 900 / 2100 HSDPA 900 / 2100
4G bands 1, 3, 5, 8, 28, 38, 40, 41 LTE
Speed HSPA, LTE HSPA 42.2/5.76 Mbps, LTE Cat4 150/50 Mbps
Technology GSM / HSPA / LTE GSM / HSPA / LTE
Platform
Chipset Qualcomm SDM439 Snapdragon 439 (12 nm) -
CPU Octa-core (4x1.95 GHz Cortex-A53 & 4x1.45 GHz Cortex A53) Quad-core 1.5 GHz
GPU Adreno 505 -
OS Android 8.1 (Oreo), Funtouch 4.5 Tizen 3.0
Selfie camera
Features - LED flash
Single 8 MP, f/2.0 5 MP, f/2.2
Video
Sound
3.5mm jack Yes Yes
Loudspeaker Yes Yes