Asus ROG Phone 5 vs. Samsung Galaxy S21 Ultra 5G: A Deep Dive Comparison

The Asus ROG Phone 5 and Samsung Galaxy S21 Ultra 5G represent distinct philosophies in the Android space. The ROG Phone 5 is unapologetically focused on gaming, prioritizing performance and features for enthusiasts. The S21 Ultra, conversely, aims for a more balanced experience, offering a top-tier camera, stunning display, and premium build quality. This comparison dissects these differences to determine which device best suits your needs.
Phones Images

🏆 Quick Verdict

For dedicated mobile gamers, the Asus ROG Phone 5 is the clear winner, offering superior cooling and gaming-centric features. However, the Samsung Galaxy S21 Ultra 5G provides a more versatile experience with a brighter display, more refined camera system, and broader appeal for everyday use.

PHONES
Phone Names Asus ROG Phone 5 Samsung Galaxy S21 Ultra 5G
Network
2G bandsGSM 850 / 900 / 1800 / 1900GSM 850 / 900 / 1800 / 1900
3G bandsHSDPA 800 / 850 / 900 / 1700(AWS) / 1800 / 1900 / 2100 - Version 1HSDPA 850 / 900 / 1700(AWS) / 1900 / 2100
4G bands1, 2, 3, 4, 5, 7, 8, 12, 13, 17, 18, 19, 20, 25, 26, 28, 29, 30, 32, 34, 38, 39, 40, 41, 42, 48, 66, 71 - Version 11, 2, 3, 4, 5, 7, 8, 12, 13, 14, 18, 19, 20, 25, 26, 28, 30, 38, 39, 40, 41, 46, 48, 66, 71 - SM-G998U1
5G bands1, 2, 3, 5, 7, 8, 12, 20, 25, 28, 38, 40, 41, 66, 71, 77, 78, 79 SA/NSA - Version 12, 5, 25, 41, 66, 71, 260, 261 SA/NSA/Sub6/mmWave - SM-G998U1
SpeedHSPA 42.2/5.76 Mbps, LTE (7CA) Cat20 1400/150 Mbps, 5G 4 Gbps DLHSPA 42.2/5.76 Mbps, LTE (7CA) Cat20 2000/200 Mbps, 5G (5+ Gbps DL)
TechnologyGSM / HSPA / LTE / 5GGSM / CDMA / HSPA / EVDO / LTE / 5G
 1, 3, 7, 8, 20, 28, 38, 41, 77, 78, 79 SA/NSA - Version 2, Version 31, 3, 5, 7, 8, 20, 28, 38, 40, 41, 66, 77, 78 SA/NSA/Sub6 - SM-G998B
Launch
Announced2021, March 102021, January 14
StatusAvailable. Released 2021, April 26Available. Released 2021, January 29
Body
BuildGlass front (Gorilla Glass Victus), glass back (Gorilla Glass 3), aluminum frameGlass front (Gorilla Glass Victus), glass back (Gorilla Glass Victus), aluminum frame
Dimensions172.8 x 77.3 x 10.3 mm (6.80 x 3.04 x 0.41 in)165.1 x 75.6 x 8.9 mm (6.5 x 2.98 x 0.35 in)
SIMNano-SIM + Nano-SIM· Nano-SIM + eSIM· Nano-SIM + Nano-SIM + eSIM (max 2 at a time)
Weight238 g (8.40 oz)227 g (Sub6), 229 g (mmWave) (8.01 oz)
 RGB light panel (on the back) Pressure sensitive zones (Gaming triggers)IP68 dust/water resistant (up to 1.5m for 30 min) Stylus support
Display
ProtectionCorning Gorilla Glass VictusCorning Gorilla Glass Victus
Resolution1080 x 2448 pixels (~395 ppi density)1440 x 3200 pixels, 20:9 ratio (~515 ppi density)
Size6.78 inches, 109.5 cm2 (~82.0% screen-to-body ratio)6.8 inches, 112.1 cm2 (~89.8% screen-to-body ratio)
TypeAMOLED, 1B colors, 144Hz, HDR10+, 800 nits (typ), 1200 nits (peak)Dynamic AMOLED 2X, 120Hz, HDR10+, 1500 nits (peak)
 -Always-on display
Platform
CPUOcta-core (1x2.84 GHz Cortex-X1 & 3x2.42 GHz Cortex-A78 & 4x1.80 GHz Cortex-A55)Octa-core (1x2.9 GHz Cortex-X1 & 3x2.80 GHz Cortex-A78 & 4x2.2 GHz Cortex-A55) - InternationalOcta-core (1x2.84 GHz Cortex-X1 & 3x2.42 GHz Cortex-A78 & 4x1.80 GHz Cortex-A55) - USA/China
ChipsetQualcomm SM8350 Snapdragon 888 5G (5 nm)Exynos 2100 (5 nm) - InternationalQualcomm SM8350 Snapdragon 888 5G (5 nm) - USA/China
GPUAdreno 660Mali-G78 MP14 - InternationalAdreno 660 - USA/China
OSAndroid 11, upgradable to Android 13, ROG UIAndroid 11, up to 4 major Android upgrades, One UI 6.1
Memory
Card slotNoNo
Internal128GB 8GB RAM, 128GB 12GB RAM, 256GB 12GB RAM, 256GB 16GB RAM128GB 8GB RAM, 128GB 12GB RAM, 256GB 12GB RAM, 256GB 16GB RAM, 512GB 12GB RAM, 512GB 16GB RAM
 UFS 3.1UFS 3.1
Main Camera
FeaturesLED flash, HDR, panoramaLaser AF, LED flash, auto-HDR, panorama
Quad-108 MP, f/1.8, 24mm (wide), 1/1.33", 0.8µm, PDAF, OIS 10 MP, f/2.4, 72mm (telephoto), 1/3.24", 1.22µm, dual pixel PDAF, OIS, 3x optical zoom 10 MP, f/4.9, 240mm (periscope telephoto), 1/3.24", 1.22µm, dual pixel PDAF, OIS, 10x optical zoom 12 MP, f/2.2, 13mm (ultrawide), 1/2.55", 1.4µm, dual pixel PDAF, Super Steady video
Triple64 MP, f/1.8, 26mm (wide), 1/1.73", 0.8µm, PDAF 13 MP, f/2.4, 11mm, 125˚ (ultrawide) 5 MP (macro)-
Video8K@30fps, 4K@30/60/120fps, 1080p@30/60/120/240fps, 720p@480fps; gyro-EIS8K@24fps, 4K@30/60fps, 1080p@30/60/120/240fps, HDR10+, stereo sound rec., gyro-EIS
Selfie camera
FeaturesPanorama, HDRHDR
Single24 MP, f/2.5, 27mm (wide), 0.9µm40 MP, f/2.2, 26mm (wide), 1/2.8", 0.7µm, PDAF
Video1080p@30fps4K@30/60fps, 1080p@30fps
Sound
3.5mm jack YesNo
35mm jackYesNo
Loudspeaker Yes, with DTS:X stereo speakers (2 dedicated amplifiers)Yes, with stereo speakers
 24-bit/192kHz audio32-bit/384kHz audio Tuned by AKG
Comms
Bluetooth5.2, A2DP, LE, aptX HD, aptX Adaptive5.2, A2DP, LE
NFCYesYes
PositioningGPS (L1+L5), GLONASS (L1), BDS (B1I+B1c+B2a), GALILEO (E1+E5a), QZSS (L1+L5), NavIC (L5)GPS, GLONASS, BDS, GALILEO
RadioNoFM radio (Snapdragon model only; market/operator dependent)
USBUSB Type-C 3.1 (side), USB Type-C 2.0 (bottom), OTG, accessory connectorUSB Type-C 3.2, OTG
WLANWi-Fi 802.11 a/b/g/n/ac/6e, dual-band, Wi-Fi DirectWi-Fi 802.11 a/b/g/n/ac/6e, dual-band, Wi-Fi Direct
Features
SensorsFingerprint (under display, optical), accelerometer, gyro, proximity, compassFingerprint (under display, ultrasonic), accelerometer, gyro, proximity, compass, barometer
 -Samsung DeX, Samsung Wireless DeX (desktop experience support) Bixby natural language commands and dictation Samsung Pay (Visa, MasterCard certified) Ultra Wideband (UWB) support
Battery
Charging65W wired, PD3.0, QC5, 70% in 30 min, 100% in 52 min 10W reverse wired25W wired, PD3.0 15W wireless (Qi) 4.5W reverse wireless
TypeLi-Po 6000 mAhLi-Ion 5000 mAh
Misc
ColorsPhantom Black, Storm WhitePhantom Black, Phantom Silver, Phantom Titanium, Phantom Navy, Phantom Brown, Navy
ModelsZS673KS, ZS673KS-1B048IN, ASUS_I005DB, ASUS_I005DA, I005DA, I005DBSM-G998B, SM-G998B/DS, SM-G998U, SM-G998U1, SM-G998W, SM-G998N, SM-G9980
PriceAbout 370 EUR$ 240.01 / C$ 353.20 / £ 202.99 / € 264.99
SAR-0.77 W/kg (head)     1.02 W/kg (body)
SAR EU-0.71 W/kg (head)     1.58 W/kg (body)
Pricing
128GB 12GB RAM-$ 384.99
256GB 12GB RAM-$ 998.00
512GB 12GB RAM-$ 1,179.99
RENEWED-$ 459.00
Tests
Battery life Endurance rating 110h Endurance rating 114h
Camera Photo / Video Photo / Video
Display Contrast ratio: Infinite (nominal) Contrast ratio: Infinite (nominal)
Loudspeaker -24.0 LUFS (Very good) -25.5 LUFS (Very good)
Performance AnTuTu: 718864 (v8) GeekBench: 14536 (v4.4), 3745 (v5.1) GFXBench: 72fps (ES 3.1 onscreen) AnTuTu: 657150 (v8) GeekBench: 3518 (v5.1) GFXBench: 33fps (ES 3.1 onscreen)

Asus ROG Phone 5

  • Significantly faster 65W charging
  • Superior cooling for sustained gaming performance
  • Gaming-centric features (AirTriggers, etc.)

  • Less versatile camera system
  • Lower peak display brightness

Samsung Galaxy S21 Ultra 5G

  • Brighter and more color-accurate display
  • More versatile and advanced camera system
  • Premium build quality and design

  • Slower 25W charging
  • Potential for thermal throttling under sustained load

Display Comparison

The Samsung Galaxy S21 Ultra 5G boasts a significantly brighter display at 1023 nits compared to the ROG Phone 5’s 806 nits, making it more visible outdoors. Both feature an 'Infinite' contrast ratio, typical of high-end OLED panels. While both offer excellent viewing experiences, the S21 Ultra’s higher peak brightness and potentially better color calibration (based on Samsung’s display expertise) give it an edge for media consumption. The ROG Phone 5’s display, while still excellent, is tuned more for gaming, potentially prioritizing response time over absolute color accuracy.

Camera Comparison

The Samsung Galaxy S21 Ultra 5G is the clear winner in camera versatility. While both phones offer photo and video capabilities, the S21 Ultra’s advanced camera system, including its larger main sensor and sophisticated image processing, delivers superior image quality, especially in challenging lighting conditions. The ROG Phone 5’s camera is competent, but it’s not a primary focus of the device. The S21 Ultra’s multiple lenses and advanced features like Space Zoom provide a wider range of creative options.

Performance

Both phones utilize the Qualcomm Snapdragon 888 5G chipset (in USA/China variants of the S21 Ultra), but the S21 Ultra’s CPU clocks slightly higher at 2.9 GHz versus the ROG Phone 5’s 2.84 GHz. However, the ROG Phone 5’s superior cooling system – a key design element – is likely to sustain peak performance for longer durations during demanding gaming sessions, mitigating potential throttling. The S21 Ultra’s performance will be excellent, but the ROG Phone 5 is engineered to maintain maximum clock speeds under sustained load. Both utilize LPDDR5 RAM, but the ROG Phone 5’s cooling advantage is the critical differentiator.

Battery Life

Both phones achieve similar endurance ratings – 110 hours for the ROG Phone 5 and 114 hours for the S21 Ultra – despite the ROG Phone 5’s faster 65W charging. The S21 Ultra offers 25W wired charging, significantly slower. The ROG Phone 5 can reach 70% charge in 30 minutes and 100% in 52 minutes, while the S21 Ultra takes considerably longer. The ROG Phone 5 also offers 10W reverse wired charging, while the S21 Ultra provides 4.5W reverse wireless charging. The ROG Phone 5’s charging speed is a significant advantage for users who need to quickly top up their battery.

Buying Guide

Buy the Asus ROG Phone 5 if you prioritize raw gaming performance, extended play sessions without throttling, and unique gaming accessories. You'll benefit from the 65W fast charging and dedicated gaming features. Buy the Samsung Galaxy S21 Ultra 5G if you value a premium camera experience, a brighter and more color-accurate display, and a more polished, all-around smartphone experience. It's the better choice for content creators and users who demand versatility.

Frequently Asked Questions

❓ Does the Exynos 2100 chip in the international S21 Ultra overheat during prolonged gaming sessions?
While the Snapdragon 888 variant generally performs slightly better, the Exynos 2100 in the international S21 Ultra can experience thermal throttling during extended gaming. However, Samsung’s software optimizations mitigate this to some extent, and the phone will still deliver a good gaming experience, albeit potentially with slightly reduced frame rates over time. The ROG Phone 5’s dedicated cooling system provides a more consistent experience.
❓ Is the 2MP macro camera on either phone actually useful for taking detailed close-up shots?
Generally, 2MP macro cameras on both devices are limited by their low resolution. While they can capture close-up images, the detail and clarity are often lacking. The S21 Ultra’s overall camera system is far more capable, and its main sensor can produce acceptable close-up shots with sufficient lighting. The ROG Phone 5’s macro camera is primarily a spec-sheet filler.
❓ Does the ROG Phone 5 support 90fps or higher frame rates in popular games like PUBG Mobile?
Yes, the ROG Phone 5 is specifically designed to support high frame rates in many popular games, including PUBG Mobile. It can achieve 90fps or even higher depending on the game settings and the phone’s cooling performance. The ‘Armoury Crate’ software allows for game-specific optimization and performance tuning.
❓ What type of charger is included in the box with each phone?
The Asus ROG Phone 5 includes a 65W HyperCharge adapter in the box. The Samsung Galaxy S21 Ultra 5G does *not* include a charger; you’ll need to use a compatible USB-C Power Delivery charger (sold separately) to achieve its maximum 25W charging speed.