Realme X9 Pro vs Samsung Galaxy S21 Ultra 5G: A Detailed Comparison

The Samsung Galaxy S21 Ultra 5G represented the pinnacle of Android flagship performance in 2021, commanding a premium price. Now, with the Realme X9 Pro offering a high-end Snapdragon 870 chipset at a significantly lower cost, the question arises: can it deliver a comparable experience? This comparison dives deep into the key differences to help you determine which phone best suits your needs.
Phones Images

🏆 Quick Verdict

For the average user prioritizing value, the Realme X9 Pro emerges as the winner. Its Snapdragon 870 provides excellent performance for daily tasks and gaming, coupled with incredibly fast 65W charging. While the S21 Ultra boasts a superior display and camera system, the price difference makes the X9 Pro a more sensible choice for most.

PHONES
Phone Names Realme X9 Pro Samsung Galaxy S21 Ultra 5G
Network
2G bandsGSM 850 / 900 / 1800 / 1900GSM 850 / 900 / 1800 / 1900
3G bandsHSDPA 800 / 850 / 900 / 1700(AWS) / 1900 / 2100HSDPA 850 / 900 / 1700(AWS) / 1900 / 2100
4G bands1, 3, 5, 8, 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 bands1, 3, 41, 77, 78 SA/NSA2, 5, 25, 41, 66, 71, 260, 261 SA/NSA/Sub6/mmWave - SM-G998U1
SpeedHSPA, LTE, 5GHSPA 42.2/5.76 Mbps, LTE (7CA) Cat20 2000/200 Mbps, 5G (5+ Gbps DL)
TechnologyGSM / CDMA / HSPA / CDMA2000 / 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
AnnouncedNot announced yet2021, January 14
StatusCancelledAvailable. Released 2021, January 29
Body
Build-Glass front (Gorilla Glass Victus), glass back (Gorilla Glass Victus), aluminum frame
Dimensions159.9 x 72.5 x 8 mm (6.30 x 2.85 x 0.31 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)
Weight185 g (6.49 oz)227 g (Sub6), 229 g (mmWave) (8.01 oz)
 -IP68 dust/water resistant (up to 1.5m for 30 min) Stylus support
Display
Protection-Corning Gorilla Glass Victus
Resolution1080 x 2400 pixels, 20:9 ratio (~402 ppi density)1440 x 3200 pixels, 20:9 ratio (~515 ppi density)
Size6.55 inches, 103.6 cm2 (~89.3% screen-to-body ratio)6.8 inches, 112.1 cm2 (~89.8% screen-to-body ratio)
TypeAMOLED, 90Hz, HDR10+Dynamic AMOLED 2X, 120Hz, HDR10+, 1500 nits (peak)
 -Always-on display
Platform
CPUOcta-core (1x3.2 GHz Kryo 585 & 3x2.42 GHz Kryo 585 & 4x1.80 GHz Kryo 585)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-AC Snapdragon 870 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 11Android 11, up to 4 major Android upgrades, One UI 6.1
Memory
Card slotNoNo
Internal128/256/512GB, 3/8/12GB RAM128GB 8GB RAM, 128GB 12GB RAM, 256GB 12GB RAM, 256GB 16GB RAM, 512GB 12GB RAM, 512GB 16GB RAM
 -UFS 3.1
Main Camera
FeaturesDual LED flash, HDR, panoramaLaser AF, LED flash, auto-HDR, panorama
Quad50 MP, f/1.8, 24mm (wide), 1/1.56", 1.0µm, multi-directional PDAF 16 MP, f/2.2, 123˚ (ultrawide), 1/3.09", 1.0µm Auxiliary lens108 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
Video4K@30/60fps, 1080p@30/60fps; gyro-EIS, HDR8K@24fps, 4K@30/60fps, 1080p@30/60/120/240fps, HDR10+, stereo sound rec., gyro-EIS
Selfie camera
FeaturesPanoramaHDR
Single32 MP, f/2.4, 26mm (wide), 1/2.8", 0.8µm40 MP, f/2.2, 26mm (wide), 1/2.8", 0.7µm, PDAF
Video1080p@30fps, gyro-EIS4K@30/60fps, 1080p@30fps
Sound
3.5mm jack -No
35mm jackNoNo
Loudspeaker YesYes, with stereo speakers
 -32-bit/384kHz audio Tuned by AKG
Comms
Bluetooth5.2, A2DP, LE, aptX HD5.2, A2DP, LE
NFCUnspecifiedYes
PositioningGPSGPS, GLONASS, BDS, GALILEO
RadioNoFM radio (Snapdragon model only; market/operator dependent)
USBUSB Type-C 3.1, OTGUSB 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
Charging65W wired 5W reverse wired25W wired, PD3.0 15W wireless (Qi) 4.5W reverse wireless
Type4500 mAhLi-Ion 5000 mAh
Misc
ColorsBlue; other coloursPhantom Black, Phantom Silver, Phantom Titanium, Phantom Navy, Phantom Brown, Navy
Models-SM-G998B, SM-G998B/DS, SM-G998U, SM-G998U1, SM-G998W, SM-G998N, SM-G9980
Price-$ 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)

Realme X9 Pro

  • Significantly faster 65W charging
  • Excellent performance for the price with Snapdragon 870
  • More affordable price point

  • Likely inferior display quality compared to S21 Ultra
  • Camera system likely less versatile and lower quality

Samsung Galaxy S21 Ultra 5G

  • Superior display brightness and quality
  • More versatile and capable camera system
  • Potentially better sustained performance (Snapdragon 888 variant)

  • Much higher price tag
  • Slower 25W charging

Display Comparison

The Samsung Galaxy S21 Ultra’s display is a clear standout, achieving a measured peak brightness of 1023 nits, ensuring excellent visibility even in direct sunlight. While the Realme X9 Pro’s display specs aren’t provided, it likely doesn’t reach this level of brightness. The S21 Ultra’s ‘Infinite’ contrast ratio, typical of AMOLED panels, delivers deep blacks and vibrant colors. The S21 Ultra also likely features an adaptive refresh rate (LTPO) for smoother scrolling and improved power efficiency, a feature not confirmed for the X9 Pro. The S21 Ultra’s larger screen size and higher resolution contribute to a more immersive viewing experience.

Camera Comparison

The Samsung Galaxy S21 Ultra’s camera system is a major strength, offering a versatile setup with multiple lenses and advanced features. While specific sensor details are not provided, the S21 Ultra is known for its exceptional image processing, particularly in low-light conditions. The X9 Pro’s camera capabilities are less detailed in the provided data, but it’s unlikely to match the S21 Ultra’s overall image quality and zoom capabilities. The S21 Ultra’s OIS (Optical Image Stabilization) is crucial for sharp photos and stable videos, especially when zoomed in. The S21 Ultra’s video recording capabilities are also superior, offering features like 8K recording.

Performance

The Samsung Galaxy S21 Ultra, depending on the region, utilizes either the Exynos 2100 (5nm) or the Qualcomm Snapdragon 888 5G (5nm). Both chips feature a Cortex-X1 prime core for peak performance, but the Snapdragon 888 generally exhibits better sustained performance and thermal management. The Realme X9 Pro’s Snapdragon 870 (7nm) is a step down in raw power, but it’s a highly efficient chip that delivers excellent performance for its class. The 870’s Kryo 585 cores, while clocked slightly lower than the 888’s, provide a smooth experience for most tasks. The S21 Ultra’s LPDDR5 RAM, combined with its more powerful processor, gives it an edge in multitasking and demanding applications. However, the X9 Pro’s 12GB of RAM is still ample for most users.

Battery Life

The Samsung Galaxy S21 Ultra boasts an endurance rating of 114 hours, indicating solid battery life. Its 25W wired charging, while decent, is significantly slower than the Realme X9 Pro’s 65W wired charging. The X9 Pro can charge from 0-100% much faster, a significant convenience for users who frequently need to top up their battery. The S21 Ultra offers 15W wireless charging and 4.5W reverse wireless charging, while the X9 Pro provides 5W reverse wired charging. While the S21 Ultra’s battery capacity isn’t specified, its endurance rating suggests a larger battery than the X9 Pro, but the faster charging of the X9 Pro mitigates this difference for many users.

Buying Guide

Buy the Realme X9 Pro if you need a powerful, fast-charging phone for gaming and everyday use without breaking the bank. It’s ideal for users who prioritize performance-per-dollar. Buy the Samsung Galaxy S21 Ultra 5G if you demand the absolute best in display quality, camera versatility, and are willing to pay a premium for those features. It caters to photography enthusiasts and power users who need a top-tier experience.

Frequently Asked Questions

❓ Does the Exynos 2100 chip in the S21 Ultra overheat during prolonged gaming sessions?
The Exynos 2100 variant of the S21 Ultra has been known to exhibit thermal throttling during extended gaming, leading to performance drops. The Snapdragon 888 variant generally handles heat better, but both can get warm. The Realme X9 Pro’s Snapdragon 870 is more efficient and less prone to overheating, offering more consistent performance over longer periods.
❓ Is the 2MP macro camera on either phone actually useful for taking detailed close-up shots?
Generally, 2MP macro cameras on smartphones are limited in quality. While they can capture close-up images, the low resolution results in a lack of detail and sharpness. The S21 Ultra’s more advanced camera system likely produces better macro shots, but dedicated macro cameras are often outperformed by using the main sensor’s close-focus capabilities.
❓ Does the Realme X9 Pro support high frame rate gaming like 90fps in PUBG Mobile?
The Snapdragon 870 is capable of running PUBG Mobile at high frame rates. While specific support depends on the game’s settings and optimization, the X9 Pro should be able to achieve 60fps or higher, and potentially 90fps with optimized settings. The S21 Ultra, with its more powerful processor, will likely offer a smoother experience at maximum settings.
❓ How does the reverse charging feature compare between the two phones, and is it useful?
The S21 Ultra offers 4.5W reverse wireless charging, while the X9 Pro provides 5W reverse wired charging. Reverse charging is a niche feature, primarily useful for topping up accessories like wireless earbuds or smartwatches in emergencies. The X9 Pro’s wired reverse charging is slightly faster, but neither is a significant selling point.