Asus ROG Phone 3 Strix vs. Samsung Galaxy S21 Ultra 5G: A Deep Dive Comparison

The Asus ROG Phone 3 Strix and the Samsung Galaxy S21 Ultra 5G represent distinct philosophies in the flagship smartphone space. The ROG Phone 3 Strix is unapologetically focused on mobile gaming, prioritizing performance and cooling, while 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 help you determine which device best suits your needs.
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🏆 Quick Verdict

For dedicated mobile gamers, the Asus ROG Phone 3 Strix is the clear winner, offering sustained performance and gaming-centric features. However, the Samsung Galaxy S21 Ultra 5G emerges as the superior choice for users prioritizing a versatile camera system, a brighter and more color-accurate display, and a more refined overall experience.

PHONES
Phone Names Asus ROG Phone 3 Strix Samsung Galaxy S21 Ultra 5G
Network
2G bandsGSM 850 / 900 / 1800 / 1900GSM 850 / 900 / 1800 / 1900
3G bandsHSDPA 850 / 900 / 1700(AWS) / 1900 / 2100HSDPA 850 / 900 / 1700(AWS) / 1900 / 2100
4G bands1, 2, 3, 4, 5, 7, 8, 20, 28, 34, 38, 39, 40, 411, 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 bands41, 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 (6CA) Cat18 1200/150 Mbps, 5G 4.0 Gbps DLHSPA 42.2/5.76 Mbps, LTE (7CA) Cat20 2000/200 Mbps, 5G (5+ Gbps DL)
TechnologyGSM / CDMA / HSPA / LTE / 5GGSM / CDMA / HSPA / EVDO / LTE / 5G
 CDMA 800 & TD-SCDMA1, 3, 5, 7, 8, 20, 28, 38, 40, 41, 66, 77, 78 SA/NSA/Sub6 - SM-G998B
Launch
Announced2020, July 22. Released 2020, July 232021, January 14
StatusDiscontinuedAvailable. Released 2021, January 29
Body
BuildGlass front (Gorilla Glass 6), glass back (Gorilla Glass 3), aluminum frameGlass front (Gorilla Glass Victus), glass back (Gorilla Glass Victus), aluminum frame
Dimensions171 x 78 x 9.9 mm (6.73 x 3.07 x 0.39 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)
Weight240 g (8.47 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 6Corning Gorilla Glass Victus
Resolution1080 x 2340 pixels, 19.5:9 ratio (~391 ppi density)1440 x 3200 pixels, 20:9 ratio (~515 ppi density)
Size6.59 inches, 106.6 cm2 (~79.9% screen-to-body ratio)6.8 inches, 112.1 cm2 (~89.8% screen-to-body ratio)
TypeAMOLED, 1B colors, 144Hz, HDR10+, 650 nits (typ)Dynamic AMOLED 2X, 120Hz, HDR10+, 1500 nits (peak)
 -Always-on display
Platform
CPUOcta-core (1x2.84 GHz Cortex-A77 & 3x2.42 GHz Cortex-A77 & 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 SM8250 Snapdragon 865 5G (7 nm+)Exynos 2100 (5 nm) - InternationalQualcomm SM8350 Snapdragon 888 5G (5 nm) - USA/China
GPUAdreno 650Mali-G78 MP14 - InternationalAdreno 660 - USA/China
OSAndroid 10, ROG UIAndroid 11, up to 4 major Android upgrades, One UI 6.1
Memory
Card slotNoNo
Internal128GB 8GB RAM, 128GB 12GB RAM, 256GB 8GB 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@30/60/240fps, 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/2.0, 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 NoNo
35mm jackNoNo
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
Bluetooth5.1, A2DP, LE, aptX HD, aptX Adaptive5.2, A2DP, LE
NFCYesYes
PositioningGPS (L1+L5), GLONASS, BDS, GALILEO, QZSSGPS, 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/6, 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
Charging30W wired, PD3.0, QC4 10W reverse wired25W wired, PD3.0 15W wireless (Qi) 4.5W reverse wireless
TypeLi-Po 6000 mAhLi-Ion 5000 mAh
Misc
ColorsBlack GlarePhantom Black, Phantom Silver, Phantom Titanium, Phantom Navy, Phantom Brown, Navy
ModelsASUS_I003DDSM-G998B, SM-G998B/DS, SM-G998U, SM-G998U1, SM-G998W, SM-G998N, SM-G9980
PriceAbout 1400 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 3 Strix

  • Superior gaming performance and cooling
  • Faster wired charging (30W)
  • Gaming-centric features like AirTriggers

  • Older chipset (Snapdragon 865)
  • Less versatile camera system
  • Display likely lacks the brightness and color accuracy of the S21 Ultra

Samsung Galaxy S21 Ultra 5G

  • Brighter and more color-accurate display
  • Versatile and high-quality camera system
  • More efficient 5nm chipset (Exynos/Snapdragon)

  • Can experience thermal throttling under sustained load
  • Slower wired charging (25W)
  • Higher price point

Display Comparison

The Samsung Galaxy S21 Ultra boasts a significantly brighter display, reaching a measured 1023 nits, compared to an unspecified peak brightness for the ROG Phone 3 Strix. While the ROG Phone 3 Strix likely has a high refresh rate, the S21 Ultra’s adaptive 120Hz LTPO panel dynamically adjusts refresh rate to conserve battery, a feature absent on the ROG Phone 3. The S21 Ultra’s ‘Infinite’ contrast ratio suggests superior black levels, enhancing visual depth. The ROG Phone 3 Strix’s display, while likely excellent for gaming, likely prioritizes refresh rate over peak brightness and color accuracy.

Camera Comparison

The Samsung Galaxy S21 Ultra’s camera system is a clear standout. While both phones offer ‘Photo/Video’ capabilities, the S21 Ultra’s sensor size and advanced image processing algorithms provide superior image quality, particularly in low-light conditions. The ROG Phone 3 Strix’s camera is likely adequate, but geared towards casual use, lacking the S21 Ultra’s professional-grade features and versatility. The S21 Ultra’s OIS (Optical Image Stabilization) is crucial for stable video recording and sharp photos, a feature likely present but less sophisticated on the ROG Phone 3 Strix. The inclusion of a 2MP macro camera on the ROG Phone 3 Strix is largely a marketing gimmick, offering minimal practical benefit.

Performance

The S21 Ultra’s chipset varies by region: the Exynos 2100 (5nm) for international markets and the Snapdragon 888 (5nm) for USA/China. Both represent a generational leap over the ROG Phone 3 Strix’s Snapdragon 865 (7nm+). The S21 Ultra’s Cortex-X1 prime core (2.9 GHz or 2.84 GHz depending on region) offers a performance advantage over the ROG Phone 3 Strix’s Cortex-A77. However, the ROG Phone 3 Strix’s superior cooling system is designed to mitigate throttling during extended gaming sessions, potentially allowing it to sustain higher clock speeds for longer periods. The S21 Ultra’s LPDDR5 RAM is standard, while the ROG Phone 3 Strix’s RAM speed is unspecified, but likely similar.

Battery Life

Both devices achieve an endurance rating of 114 hours, suggesting comparable battery life despite the ROG Phone 3 Strix’s unspecified battery capacity. However, the S21 Ultra offers more versatile charging options: 25W wired, 15W wireless (Qi), and 4.5W reverse wireless. The ROG Phone 3 Strix supports 30W wired charging, PD3.0, and QC4, along with 10W reverse wired charging. While the ROG Phone 3 Strix’s faster wired charging is beneficial, the S21 Ultra’s wireless charging capabilities provide added convenience. The S21 Ultra’s efficient 5nm chipset contributes to its strong battery performance.

Buying Guide

Buy the Asus ROG Phone 3 Strix if you demand maximum gaming performance, prioritize sustained frame rates over all else, and appreciate features like AirTriggers. Buy the Samsung Galaxy S21 Ultra 5G if you value a top-tier camera experience, a stunning display for media consumption, and a more polished, all-around smartphone experience with broader functionality beyond gaming.

Frequently Asked Questions

❓ Does the Exynos 2100 chip in the international S21 Ultra overheat during prolonged gaming sessions?
While the Exynos 2100 can generate more heat than the Snapdragon 888, Samsung implemented effective thermal management solutions in the S21 Ultra. However, sustained gaming at maximum settings may still lead to some throttling, reducing peak performance over extended periods. The ROG Phone 3 Strix, with its dedicated cooling system, is better equipped to handle prolonged gaming without significant throttling.
❓ Is the 2MP macro camera on the ROG Phone 3 Strix actually useful for taking detailed close-up photos?
Generally, 2MP macro cameras offer limited detail and image quality. The small sensor size and lack of optical image stabilization result in soft, noisy images. While it can be used for experimentation, it's unlikely to produce professional-looking macro photographs. The S21 Ultra does not include a dedicated macro camera, instead relying on its main sensor's close-focusing capabilities for superior results.
❓ Can the Asus ROG Phone 3 Strix reliably maintain 90fps in demanding games like PUBG Mobile?
The ROG Phone 3 Strix is capable of achieving high frame rates in PUBG Mobile, but maintaining a consistent 90fps depends on the game settings and the duration of the gameplay session. The phone's cooling system helps to prevent throttling, but prolonged gaming at maximum settings may still result in frame rate drops. Lowering graphics settings can help to stabilize the frame rate.
❓ What are the benefits of the PD3.0 and QC4 charging standards supported by the ROG Phone 3 Strix?
PD3.0 (Power Delivery) and QC4 (Quick Charge) are fast-charging standards that allow the ROG Phone 3 Strix to charge more quickly when used with compatible chargers. These standards negotiate the optimal voltage and current for faster and more efficient charging, reducing charging times compared to standard USB charging.