Product
Vivo S1 Pro
Vivo S1 Pro
Xiaomi Redmi K20
Xiaomi Redmi K20
Battery
Charging 18W wired 18W wired
Type 4500 mAh, non-removable Li-Po 4000 mAh, non-removable
Body
Build Glass front, glass back, aluminum frame Glass front (Gorilla Glass 5), glass back (Gorilla Glass 5), aluminum frame
Dimensions 159.3 x 75.2 x 8.7 mm (6.27 x 2.96 x 0.34 in) 156.7 x 74.3 x 8.8 mm (6.17 x 2.93 x 0.35 in)
SIM Nano-SIMNano-SIM + Nano-SIM Nano-SIM + Nano-SIM
Weight 186.7 g (6.60 oz) 191 g (6.74 oz)
Comms
Bluetooth 5.0, A2DP, LE 5.0, A2DP, LE, aptX HD
NFC No Yes (China only)
Positioning GPS, GLONASS, GALILEO, BDS GPS, GLONASS, GALILEO, BDS
Radio FM radio FM radio
USB USB Type-C 2.0, OTG USB Type-C 2.0, OTG
WLAN Wi-Fi 802.11 a/b/g/n/ac, dual-band, Wi-Fi Direct Wi-Fi 802.11 a/b/g/n/ac, dual-band, Wi-Fi Direct
Display
Protection - Corning Gorilla Glass 5
Resolution 1080 x 2340 pixels, 19.5:9 ratio (~404 ppi density) 1080 x 2340 pixels, 19.5:9 ratio (~403 ppi density)
Size 6.38 inches, 99.9 cm2 (~83.4% screen-to-body ratio) 6.39 inches, 100.2 cm2 (~86.1% screen-to-body ratio)
Type Super AMOLED Super AMOLED, HDR
Features
Sensors Fingerprint (under display, optical), accelerometer, gyro, proximity, compass Fingerprint (under display, optical), accelerometer, gyro, proximity, compass
Launch
Announced 2019, November 19. Released 2019, November 2019, May. Released 2019, June
Status Discontinued Discontinued
Main Camera
Features LED flash, HDR, panorama Dual-LED flash, HDR, panorama
Quad 48 MP, f/1.8, (wide), 1/2.0", 0.8µm, PDAF 8 MP, f/2.2, 13mm (ultrawide), 1/4.0", 1.12µm 2 MP, f/2.4, (macro) 2 MP, f/2.4, (depth) -
Triple - 48 MP, f/1.8, 26mm (wide), 1/2.0", 0.8µm, PDAF 8 MP, f/2.4, 53mm (telephoto), 1/4.0", 1.12µm, PDAF, 2x optical zoom 13 MP, f/2.4, 12mm (ultrawide), 1/3.1", 1.12µm
Video 1080p@30fps 4K@30fps, 1080p@30/120/240fps, 1080p@960fps
Memory
Card slot microSDXC (uses shared SIM slot) No
Internal 128GB 8GB RAM 64GB 6GB RAM, 128GB 6GB RAM, 256GB 8GB RAM
  - UFS 2.1
Misc
Colors Knight Black, Fancy Sky Carbon black, Red flame, Glacier blue, Pearl White
Models 1920, PD1945F_EX, 1920_20 M1903F10I
SAR - 1.07 W/kg (head)     0.72 W/kg (body)    
Network
2G bands GSM 850 / 900 / 1800 / 1900 GSM 850 / 900 / 1800 / 1900
3G bands HSDPA 850 / 900 / 2100 HSDPA 850 / 900 / 1900 / 2100
4G bands 1, 3, 5, 28, 38, 40, 41 1, 3, 5, 7, 8, 34, 38, 39, 40, 41
Speed HSPA, LTE HSPA, LTE
Technology GSM / HSPA / LTE GSM / HSPA / LTE
Platform
Chipset Qualcomm SDM665 Snapdragon 665 (11 nm) Qualcomm SDM730 Snapdragon 730 (8 nm)
CPU Octa-core (4x2.0 GHz Kryo 260 Gold & 4x1.8 GHz Kryo 260 Silver) Octa-core (2x2.2 GHz Kryo 470 Gold & 6x1.8 GHz Kryo 470 Silver)
GPU Adreno 610 Adreno 618
OS Android 9.0 (Pie), Funtouch 9.2 Android 9.0 (Pie), upgradable to Android 10, MIUI 12
Selfie camera
Features HDR HDR
Single 32 MP, f/2.0, 26mm (wide), 1/2.8", 0.8µm Motorized pop-up 20 MP, f/2.2, (wide), 1/3.4", 0.8µm
Video 1080p@30fps 1080p@30fps
Sound
3.5mm jack Yes Yes
Loudspeaker Yes Yes
  - 24-bit/192kHz Hi-Res audio