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

The Asus ROG Phone 5 Pro and Samsung Galaxy S21 Ultra 5G represent distinct philosophies in the flagship smartphone space. The ROG Phone 5 Pro is unapologetically geared towards mobile gaming, prioritizing performance and features for enthusiasts. Conversely, the S21 Ultra aims for a more balanced experience, excelling in photography, display quality, and everyday usability. This comparison dissects their strengths and weaknesses to determine which device reigns supreme for different user needs.
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🏆 Quick Verdict

For dedicated mobile gamers, the Asus ROG Phone 5 Pro is the clear winner, offering superior cooling, faster charging, and gaming-centric features. However, the Samsung Galaxy S21 Ultra 5G provides a more polished, versatile experience with a class-leading camera and brighter display, making it the better choice for mainstream users.

PHONES
Phone Names Asus ROG Phone 5 Pro 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 / 2100HSDPA 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, 711, 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/NSA2, 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, 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, July 02Available. 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)
 Pressure sensitive zones (Gaming triggers) Touch sensor; ROG Vision color PMOLED display (on the back)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
Internal512GB 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
ColorsGlossy BlackPhantom Black, Phantom Silver, Phantom Titanium, Phantom Navy, Phantom Brown, Navy
ModelsZS673KS, ZS673KS-1A079INSM-G998B, SM-G998B/DS, SM-G998U, SM-G998U1, SM-G998W, SM-G998N, SM-G9980
PriceAbout 680 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 114h
Camera- Photo / Video
Display- Contrast ratio: Infinite (nominal)
Loudspeaker- -25.5 LUFS (Very good)
Performance- AnTuTu: 657150 (v8) GeekBench: 3518 (v5.1) GFXBench: 33fps (ES 3.1 onscreen)

Asus ROG Phone 5 Pro

  • Significantly faster 65W charging
  • Superior cooling system for sustained gaming
  • Gaming-centric features like AirTriggers

  • Less versatile camera system
  • Potentially bulkier design

Samsung Galaxy S21 Ultra 5G

  • Exceptional camera performance
  • Brighter and potentially more efficient display
  • More refined software experience

  • Slower 25W charging
  • Exynos variant may exhibit more thermal throttling

Display Comparison

The Samsung Galaxy S21 Ultra boasts a peak brightness of 1023 nits, ensuring excellent visibility even in direct sunlight. While the ROG Phone 5 Pro’s display specs aren’t explicitly provided, its focus on gaming suggests a high refresh rate panel. The S21 Ultra’s ‘Infinite’ contrast ratio, typical of AMOLED displays, delivers deep blacks and vibrant colors. The S21 Ultra’s display technology is likely LTPO, enabling variable refresh rates for improved power efficiency, a feature not confirmed for the ROG Phone 5 Pro. This makes the S21 Ultra the better choice for media consumption and outdoor use.

Camera Comparison

The S21 Ultra’s camera system is a significant strength, offering a versatile setup with multiple lenses and advanced image processing. While specific sensor details are missing, the S21 Ultra’s reputation for photographic excellence is well-established. The ROG Phone 5 Pro’s camera is likely competent, but it’s not the primary focus of the device. The S21 Ultra’s superior image processing and potentially larger sensors (implied by its camera reputation) will result in better low-light performance and overall image quality. The inclusion of features like 8K video recording further solidifies the S21 Ultra’s camera advantage.

Performance

Both phones utilize the Qualcomm Snapdragon 888 5G chipset in some regions (USA/China for both). However, the international S21 Ultra uses the Exynos 2100. While both are 5nm chips, the Snapdragon 888 generally exhibits slightly better sustained performance and thermal efficiency. The ROG Phone 5 Pro’s advanced cooling system is a key differentiator, allowing it to maintain peak performance for longer gaming sessions. The S21 Ultra’s CPU clocks slightly higher (2.9 GHz vs 2.84 GHz on the USA/China S21 Ultra and ROG Phone 5 Pro’s primary core), but this difference is unlikely to be noticeable in real-world usage. The ROG Phone 5 Pro’s focus on gaming means it’s optimized for sustained performance, potentially mitigating any theoretical CPU advantage of the S21 Ultra.

Battery Life

Both devices have an endurance rating of 114 hours, suggesting comparable battery life under similar usage conditions. However, the ROG Phone 5 Pro’s 65W wired charging is significantly faster than the S21 Ultra’s 25W charging. The ROG Phone 5 Pro can reach 70% charge in 30 minutes and 100% in 52 minutes, while the S21 Ultra takes considerably longer. The ROG Phone 5 Pro also offers 10W reverse wired charging, while the S21 Ultra provides 4.5W reverse wireless charging. This faster charging capability gives the ROG Phone 5 Pro a practical advantage for users who frequently need to top up their battery quickly.

Buying Guide

Buy the Asus ROG Phone 5 Pro if you prioritize uncompromising gaming performance, need the fastest possible charging speeds, and value features like AirTriggers and a high refresh rate display for competitive gaming. Buy the Samsung Galaxy S21 Ultra 5G if you want a premium all-rounder with an exceptional camera system, a stunning display, and a more refined software experience for everyday use and content creation.

Frequently Asked Questions

❓ Does the Exynos 2100 chip in the international S21 Ultra overheat during prolonged gaming sessions?
The Exynos 2100 has been known to exhibit more thermal throttling than the Snapdragon 888 under sustained load. While the S21 Ultra has a capable cooling system, it may not be as effective as the ROG Phone 5 Pro’s, potentially leading to reduced performance during extended gaming.
❓ Is the 2MP macro camera on the S21 Ultra actually useful for detailed close-up shots?
While present, the 2MP macro camera on the S21 Ultra is often considered a marketing feature rather than a significant improvement to image quality. Its limited resolution and sensor size result in images that lack detail compared to using the main sensor with digital zoom.
❓ Does the ROG Phone 5 Pro support 90fps or higher frame rates in popular games like PUBG Mobile?
Yes, the ROG Phone 5 Pro is specifically designed to support high frame rates in many popular games, including PUBG Mobile. Its powerful hardware and optimized software allow for smooth gameplay at 90fps or even higher, depending on the game settings.
❓ How does the reverse charging feature compare between the two phones for topping up accessories?
The ROG Phone 5 Pro’s 10W reverse *wired* charging is more practical for quickly topping up accessories than the S21 Ultra’s 4.5W reverse *wireless* charging. The wired connection provides a faster and more efficient transfer of power.