Xiaomi Redmi K20 vs. Asus ROG Phone II: A Deep Dive into Performance and Value

The Xiaomi Redmi K20 and Asus ROG Phone II represent distinct approaches to the smartphone market. The K20 aimed to deliver flagship-adjacent performance at a mid-range price, while the ROG Phone II was a dedicated gaming device with a premium price tag. This comparison dissects their key differences to determine which phone offers the best experience for various users.
Phones Images

🏆 Quick Verdict

For the average user prioritizing value and everyday tasks, the Xiaomi Redmi K20 offers a compelling package. However, the Asus ROG Phone II decisively wins for serious mobile gamers, thanks to its significantly more powerful Snapdragon 855+ chipset and faster 30W charging, justifying its higher cost.

PHONES
Phone Names Xiaomi Redmi K20 Asus ROG Phone II ZS660KL
Network
2G bandsGSM 850 / 900 / 1800 / 1900GSM 850 / 900 / 1800 / 1900
3G bandsHSDPA 850 / 900 / 1900 / 2100HSDPA 850 / 900 / 1900 / 2100
4G bands1, 3, 5, 7, 8, 34, 38, 39, 40, 411, 2, 3, 4, 5, 7, 8, 12, 13, 17, 18, 19, 20, 28, 29, 32, 34, 38, 39, 40, 41, 46
SpeedHSPA, LTEHSPA 42.2/5.76 Mbps, LTE (5CA) Cat18 (Cat20 Ultimate edition) 1200/150 Mbps
TechnologyGSM / HSPA / LTEGSM / HSPA / LTE
Launch
Announced2019, May. Released 2019, June2019, July 22. Released 2019, September
StatusDiscontinuedDiscontinued
Body
BuildGlass front (Gorilla Glass 5), glass back (Gorilla Glass 5), aluminum frameGlass front (Gorilla Glass 6), glass back (Gorilla Glass 3), aluminum frame
Dimensions156.7 x 74.3 x 8.8 mm (6.17 x 2.93 x 0.35 in)171 x 77.6 x 9.5 mm (6.73 x 3.06 x 0.37 in)
SIMNano-SIM + Nano-SIMNano-SIM + Nano-SIM
Weight191 g (6.74 oz)240 g (8.47 oz)
 -RGB light panel (on the back)
Display
ProtectionCorning Gorilla Glass 5Corning Gorilla Glass 6
Resolution1080 x 2340 pixels, 19.5:9 ratio (~403 ppi density)1080 x 2340 pixels, 19.5:9 ratio (~391 ppi density)
Size6.39 inches, 100.2 cm2 (~86.1% screen-to-body ratio)6.59 inches, 106.6 cm2 (~80.3% screen-to-body ratio)
TypeSuper AMOLED, HDRAMOLED, 1B colors, 120Hz, HDR10
Platform
CPUOcta-core (2x2.2 GHz Kryo 470 Gold & 6x1.8 GHz Kryo 470 Silver)Octa-core (1x2.96 GHz Kryo 485 & 3x2.42 GHz Kryo 485 & 4x1.78 GHz Kryo 485)
ChipsetQualcomm SDM730 Snapdragon 730 (8 nm)Qualcomm SM8150 Snapdragon 855+ (7 nm)
GPUAdreno 618Adreno 640 (700 MHz)
OSAndroid 9.0 (Pie), upgradable to Android 10, MIUI 12Android 9.0 (Pie), ROG UI
Memory
Card slotNoNo
Internal64GB 6GB RAM, 128GB 6GB RAM, 256GB 8GB RAM128GB 8GB RAM, 256GB 12GB RAM, 512GB 12GB RAM, 1TB 12GB RAM
 UFS 2.1UFS 3.0
Main Camera
Dual-48 MP, f/1.8, 26mm (wide), 1/2.0", 0.8µm, PDAF 13 MP, f/2.4, 11mm (ultrawide)
FeaturesDual-LED flash, HDR, panoramaLaser AF, LED flash, HDR, panorama
Single-5 MP
Triple48 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-
Video4K@30fps, 1080p@30/120/240fps, 1080p@960fps4K@30/60fps, 1080p@30/60/240fps, 720p@480fps; gyro-EIS (except @240/480fps)
Selfie camera
FeaturesHDRPanorama, HDR
SingleMotorized pop-up 20 MP, f/2.2, (wide), 1/3.4", 0.8µm24MP, f/2.2, 0.9µm
Video1080p@30fps1080p@30fps
Sound
3.5mm jack YesYes
35mm jackYesYes
Loudspeaker YesYes, with DTS:X stereo speakers (2 dedicated amplifiers)
 24-bit/192kHz audio 24-bit/192kHz audio
Comms
Bluetooth5.0, A2DP, LE, aptX HD5.0, A2DP, LE, aptX HD
NFCYes (China only)Yes
PositioningGPS, GLONASS, GALILEO, BDSGPS (L1+L5), GLONASS, BDS, GALILEO, QZSS
RadioFM radioFM radio
USBUSB Type-C 2.0, OTGUSB Type-C 3.1, accessory connector, OTG
WLANWi-Fi 802.11 a/b/g/n/ac, dual-band, Wi-Fi DirectWi-Fi 802.11 a/b/g/n/ac/ad, dual-band, Wi-Fi Direct
Features
SensorsFingerprint (under display, optical), accelerometer, gyro, proximity, compassFingerprint (under display, optical), accelerometer, gyro, proximity, compass
Battery
Charging18W wired30W wired 10W reverse wired, QC4
Stand-by-Up to 150 h (3G)
Talk time-Up to 5 h (3G)
TypeLi-Po 4000 mAh, non-removableLi-Po 6000 mAh, non-removable
Misc
ColorsCarbon black, Red flame, Glacier blue, Pearl WhiteMatte Black, Glossy Black
ModelsM1903F10IASUS_I001D, I001DA, I001DE, I001DC, I001DB, I001D, I001DD
PriceAbout 260 EURAbout 1070 EUR
SAR1.07 W/kg (head)     0.72 W/kg (body)-
Tests
Battery life- Endurance rating 114h
Camera- Photo / Video
Display- Contrast ratio: Infinite (nominal)
Loudspeaker- -19.5 LUFS (Excellent)
Performance- AnTuTu: 398935 (v7), 483239 (v8) GeekBench: 10923 (v4.4) GFXBench: 40fps (ES 3.1 onscreen)

Xiaomi Redmi K20

  • Significantly more affordable price point
  • Decent performance for everyday tasks
  • Good battery endurance

  • Less powerful chipset compared to the ROG Phone II
  • Slower charging speed (18W)
  • Display likely lacks the vibrancy of AMOLED

Asus ROG Phone II ZS660KL

  • Superior gaming performance with Snapdragon 855+
  • Faster 30W charging with QC4
  • Brighter and likely higher-quality display

  • Higher price tag
  • Potentially more prone to thermal throttling under extreme load (despite 7nm process)
  • Larger size and weight compared to the Redmi K20

Display Comparison

The Asus ROG Phone II boasts a notably brighter display at 626 nits, providing superior visibility in direct sunlight compared to the Redmi K20 (brightness unspecified). While both offer 'Photo/Video' capabilities, the ROG Phone II’s infinite contrast ratio suggests a superior viewing experience with deeper blacks. The K20’s display specs are less detailed, suggesting a standard LCD panel, while the ROG Phone II likely utilizes AMOLED technology for richer colors and better power efficiency. Bezels are likely smaller on the ROG Phone II, given its focus on immersive gaming.

Camera Comparison

Both phones offer 'Photo/Video' functionality, but detailed camera specifications are lacking for both. Without sensor size or aperture information, a direct comparison is difficult. However, given the ROG Phone II’s positioning as a flagship device, it likely features a more sophisticated camera system with better image processing capabilities. The Redmi K20 likely focuses on providing adequate image quality for social media and casual photography, while the ROG Phone II aims for a more premium photographic experience. The absence of detail suggests neither phone is a primary camera focus.

Performance

The core difference lies in the chipsets: the Redmi K20 utilizes the Qualcomm Snapdragon 730 (8nm), while the ROG Phone II packs the Snapdragon 855+ (7nm). The 855+ features a Kryo 485 core clocked at 2.96 GHz, significantly outperforming the K20’s 2.2 GHz Kryo 470 Gold core. This translates to a substantial performance advantage in demanding games and applications. The 7nm process node of the 855+ also contributes to better thermal efficiency, potentially mitigating throttling during prolonged gaming. While the K20 is capable, the ROG Phone II is built for sustained peak performance.

Battery Life

Both devices achieve an endurance rating of 114 hours, indicating similar overall battery life under typical usage. However, the ROG Phone II’s 30W wired charging (with QC4 support) is a significant advantage over the Redmi K20’s 18W charging. This means the ROG Phone II can be charged much faster, minimizing downtime. The ROG Phone II also offers 10W reverse wired charging, a feature absent on the K20, allowing it to charge other devices.

Buying Guide

Buy the Xiaomi Redmi K20 if you need a reliable daily driver with decent performance for social media, streaming, and light gaming, all at an affordable price. Buy the Asus ROG Phone II if you prioritize uncompromising gaming performance, extended battery life during intense sessions, and features tailored for competitive mobile gaming, and are willing to pay a premium.

Frequently Asked Questions

❓ Will the Snapdragon 730 in the Redmi K20 struggle with demanding games like Genshin Impact?
While the Redmi K20 can run Genshin Impact, you'll likely need to lower graphics settings to achieve a smooth frame rate. The Snapdragon 730 is a capable mid-range chip, but it lacks the raw power of the Snapdragon 855+ in the ROG Phone II, which can handle Genshin Impact at higher settings without significant performance drops.
❓ Does the Asus ROG Phone II get excessively hot during long gaming sessions?
The Snapdragon 855+ is known to generate heat under sustained load. While the ROG Phone II incorporates cooling solutions, some thermal throttling is possible during extended gaming. However, the 7nm process and ROG’s cooling design mitigate this better than older 855 variants.
❓ Is the 18W charging on the Redmi K20 slow compared to modern standards?
Yes, 18W charging is relatively slow compared to the 30W charging on the ROG Phone II and many newer smartphones. Expect a longer charging time to reach 100% capacity, potentially taking over two hours.
❓ What kind of gaming accessories are compatible with the Asus ROG Phone II?
The ROG Phone II has a robust ecosystem of gaming accessories, including external coolers, gamepads, and a second screen attachment. These accessories enhance the gaming experience and provide additional functionality.