The Samsung Galaxy A51, a mainstay of the mid-range for years, now faces a newer contender: the Xiaomi Redmi Note 9 Pro 5G. While the A51 benefited from early market adoption and brand recognition, the Redmi Note 9 Pro 5G arrives with a more modern chipset and faster charging, creating a compelling head-to-head. This comparison dissects the key differences to determine which phone offers the best value in 2024.
🏆 Quick Verdict
For most users, the Xiaomi Redmi Note 9 Pro 5G is the better choice. Its Snapdragon 750G chipset, built on an 8nm process, delivers superior performance and efficiency compared to the older 10nm Exynos 9611 in the Galaxy A51. The significantly faster 33W charging also provides a substantial convenience advantage, offsetting the A51’s slightly better endurance rating.
| Network |
|---|
| 2G bands | GSM 850 / 900 / 1800 / 1900 | GSM 850 / 900 / 1800 / 1900 |
| 3G bands | HSDPA 850 / 900 / 1900 / 2100 | HSDPA 850 / 900 / 1900 / 2100 |
| 4G bands | 1, 2, 3, 4, 5, 7, 8, 12, 13, 17, 20, 26, 28, 38, 40, 41, 66 | 1, 3, 5, 7, 8, 34, 38, 39, 40, 41 |
| 5G bands | - | 1, 3, 41, 78, 79 SA/NSA/Sub6 |
| Speed | HSPA, LTE | HSPA, LTE, 5G |
| Technology | GSM / HSPA / LTE | GSM / CDMA / HSPA / EVDO / LTE / 5G |
| | 2, 4, 5, 12, 13, 25, 26, 41, 66, 71 - SM-A515U | CDMA2000 1xEV-DO |
| Launch |
|---|
| Announced | 2019, December 12. Released 2019, December 16 | 2020, November 26 |
| Status | Discontinued | Available. Released 2020, December 01 |
| Body |
|---|
| Build | Glass front (Gorilla Glass 3), plastic back, plastic frame | Glass front (Gorilla Glass 5), glass back (Gorilla Glass 5) |
| Dimensions | 158.5 x 73.6 x 7.9 mm (6.24 x 2.90 x 0.31 in) | 165.4 x 76.8 x 9 mm (6.51 x 3.02 x 0.35 in) |
| SIM | · Nano-SIM· Nano-SIM + Nano-SIM | Nano-SIM + Nano-SIM |
| Weight | 172 g (6.07 oz) | 215 g (7.58 oz) |
| | - | IP53, dust and splash resistant |
| Display |
|---|
| Protection | Corning Gorilla Glass 3 | Corning Gorilla Glass 5 |
| Resolution | 1080 x 2400 pixels, 20:9 ratio (~405 ppi density) | 1080 x 2400 pixels, 20:9 ratio (~395 ppi density) |
| Size | 6.5 inches, 102.0 cm2 (~87.4% screen-to-body ratio) | 6.67 inches, 107.4 cm2 (~84.6% screen-to-body ratio) |
| Type | Super AMOLED | IPS LCD, HDR10, 120Hz, 450 nits (typ) |
| Platform |
|---|
| CPU | Octa-core (4x2.3 GHz Cortex-A73 & 4x1.7 GHz Cortex-A53) | Octa-core (2x2.2 GHz Kryo 570 & 6x1.8 GHz Kryo 570) |
| Chipset | Exynos 9611 (10 nm) | Qualcomm SM7225 Snapdragon 750G 5G (8 nm) |
| GPU | Mali-G72 MP3 | Adreno 619 |
| OS | Android 10, upgradable to Android 13, One UI 5 | Android 10, MIUI 12 |
| Memory |
|---|
| Card slot | microSDXC (dedicated slot) | microSDXC (uses shared SIM slot) |
| Internal | 64GB 4GB RAM, 64GB 6GB RAM, 128GB 4GB RAM, 128GB 6GB RAM, 128GB 8GB RAM, 256GB 6GB RAM, 256GB 8GB RAM | 128GB 6GB RAM, 128GB 8GB RAM, 256GB 8GB RAM |
| | UFS 2.0 | UFS 2.2 |
| Main Camera |
|---|
| Features | LED flash, panorama, HDR | Dual-LED dual-tone flash, HDR, panorama |
| Quad | 48 MP, f/2.0, 26mm (wide), 1/2.0", 0.8µm, PDAF
12 MP, f/2.2, 123˚ (ultrawide)
5 MP (macro)
Auxiliary lens | 108 MP, f/1.8, 26mm (wide), 1/1.52", 0.7µm, PDAF
8 MP, f/2.2, 118˚ (ultrawide), 1/4.0", 1.12µm
2 MP (macro)
Auxiliary lens |
| Video | 4K@30fps, 1080p@30/120fps; gyro-EIS | 4K@30fps, 1080p@30/60fps, gyro-EIS |
| Selfie camera |
|---|
| Features | HDR | HDR, panorama |
| Single | 32 MP, f/2.2, 26mm (wide), 1/2.8", 0.8µm | 16 MP, f/2.5, (wide), 1/3.06", 1.0µm |
| Video | 4K@30fps, 1080p@30fps | 1080p@30fps, gyro-EIS |
| Sound |
|---|
| 3.5mm jack | Yes | Yes |
| 35mm jack | Yes | Yes |
| Loudspeaker | Yes | Yes, with stereo speakers |
| | - | 24-bit/192kHz audio |
| Comms |
|---|
| Bluetooth | 5.0, A2DP, LE | 5.1, A2DP, LE |
| Infrared port | - | Yes |
| NFC | Yes | Yes |
| Positioning | GPS, GLONASS, GALILEO, BDS | GPS (L1+L5), GLONASS (G1), BDS (B1I+B2a), GALILEO (E1+E5a), QZSS (L1+L5) |
| Radio | FM radio | Unspecified |
| USB | USB Type-C 2.0, OTG | USB Type-C 2.0 |
| WLAN | Wi-Fi 802.11 a/b/g/n/ac, dual-band, Wi-Fi Direct | Wi-Fi 802.11 a/b/g/n/ac, dual-band, Wi-Fi Direct |
| Features |
|---|
| Sensors | Fingerprint (under display, optical), accelerometer, gyro, compass | Fingerprint (side-mounted), accelerometer, gyro, compass |
| | Virtual proximity sensing
ANT+ | Virtual proximity sensing |
| Battery |
|---|
| Charging | 15W wired | 33W wired, 100% in 58 min |
| Type | Li-Po 4000 mAh, non-removable | Li-Po 4820 mAh |
| Misc |
|---|
| Colors | Prism Crush Black, Prism Crush White, Prism Crush Blue, Prism Crush Pink | Gray, Blue, Red/Mint |
| Models | SM-A515F, SM-A515F/DSN, SM-A515F/DS, SM-A515F/DST, SM-A515F/DSM, SM-A515F/N, SM-A515U, SM-A515U1, SM-A515W, SM-A515X, SM-S515DL | M2007J17C |
| Price | About 100 EUR | About 370 EUR |
| SAR | 0.80 W/kg (head) 0.67 W/kg (body) | - |
| SAR EU | 0.37 W/kg (head) 1.59 W/kg (body) | - |
| Pricing |
|---|
| 128GB 4GB RAM | $ 299.99 | - |
| 128GB 6GB RAM | $ 674.99 | - |
| 64GB 4GB RAM | $ 211.50 | - |
| RENEWED | £ 179.00 | - |
| Tests |
|---|
| Audio quality |
Noise -93.1dB / Crosstalk -87.3dB | - |
| Battery life |
Endurance rating 86h
| - |
| Camera |
Photo / Video | - |
| Display |
Contrast ratio: Infinite (nominal) | - |
| Loudspeaker |
-28.6 LUFS (Average)
| - |
| Performance |
AnTuTu: 113051 (v7), 175363 (v8)
GeekBench: 5401 (v4.4), 1294 (v5.1)
GFXBench: 5.6fps (ES 3.1 onscreen) | - |
Samsung Galaxy A51
- Established brand reputation
- Good battery endurance (86h)
- Vibrant AMOLED display (636 nits)
- Older, less efficient Exynos 9611 chipset
- Slow 15W charging
- Potentially higher price for older hardware
Xiaomi Redmi Note 9 Pro 5G
- More modern and efficient Snapdragon 750G 5G chipset
- Ultra-fast 33W charging (0-100% in 58 min)
- Likely better long-term software support
- Display specifications largely unknown
- Less established brand recognition
- Potential for aggressive software customization
Display Comparison
The Samsung Galaxy A51 boasts a measured peak brightness of 636 nits, a respectable figure for outdoor visibility. However, the Redmi Note 9 Pro 5G’s display specifications are not provided, making a direct comparison difficult. Given Xiaomi’s typical approach in this segment, it’s likely to offer similar brightness levels. The A51’s ‘Infinite’ contrast ratio is a marketing term, but suggests a typical AMOLED panel with deep blacks. Without knowing the panel technology of the Redmi Note 9 Pro 5G, it’s hard to assess color accuracy or viewing angles, but the A51’s AMOLED panel is generally known for vibrant colors.
Camera Comparison
Both devices are listed as having 'Photo / Video' capabilities, lacking specific details. Without sensor size, aperture, or OIS information, a detailed camera comparison is impossible. However, it’s reasonable to assume the Redmi Note 9 Pro 5G, being a newer device, may incorporate more advanced image processing algorithms. The prevalence of 2MP macro cameras on both devices suggests they are largely marketing features with limited practical utility. Real-world image quality will depend heavily on software optimization, but the Snapdragon 750G’s ISP (Image Signal Processor) is likely more advanced.
Performance
The core difference lies in the chipsets. The Samsung Galaxy A51’s Exynos 9611, fabricated on a 10nm process, features an octa-core configuration with Cortex-A73 and A53 cores. The Xiaomi Redmi Note 9 Pro 5G, however, utilizes the Qualcomm Snapdragon 750G 5G, built on a more efficient 8nm process. This process node advantage, combined with Qualcomm’s Kryo 570 cores, translates to better sustained performance and thermal management. While both are octa-core CPUs, the Snapdragon 750G’s architecture is demonstrably more modern and capable, offering a smoother experience for demanding applications and games. The A51 may show signs of throttling under prolonged load due to its less efficient chipset.
Battery Life
The Samsung Galaxy A51 achieves an endurance rating of 86 hours, indicating solid battery life. However, the Xiaomi Redmi Note 9 Pro 5G compensates for any potential capacity difference with its significantly faster 33W wired charging, achieving a full charge in just 58 minutes. The A51’s 15W charging is considerably slower. While the A51’s endurance rating is good, the convenience of quickly topping up the Redmi Note 9 Pro 5G’s battery is a major advantage for users who don’t want to be tethered to a charger for hours.
Buying Guide
Buy the Samsung Galaxy A51 if you prioritize established brand reliability and potentially find a significantly discounted unit, accepting compromises in performance and charging speed. Buy the Xiaomi Redmi Note 9 Pro 5G if you value a more modern chipset for smoother multitasking and gaming, coupled with the convenience of rapid 33W charging, making it ideal for power users and those frequently on the go.
Frequently Asked Questions
❓ Does the Exynos 9611 in the Galaxy A51 overheat during extended gaming sessions?
The Exynos 9611, being a 10nm chip, is prone to thermal throttling under sustained load. While it can handle casual gaming, demanding titles may experience frame drops and reduced performance after prolonged play. The Redmi Note 9 Pro 5G’s Snapdragon 750G, built on an 8nm process, is significantly more efficient and less likely to overheat.
❓ Is the 33W charging on the Redmi Note 9 Pro 5G compatible with Power Delivery (PD) chargers?
While the Redmi Note 9 Pro 5G supports 33W charging, it utilizes Xiaomi’s proprietary charging protocol. While it *may* work with some PD chargers, it won’t achieve the full 33W speed unless you use a compatible Xiaomi charger. Using a standard USB-PD charger will likely result in slower charging speeds.
❓ How does the software experience differ between Samsung's One UI and Xiaomi's MIUI?
Samsung’s One UI is generally considered more polished and refined, with a cleaner aesthetic and fewer pre-installed apps. Xiaomi’s MIUI, while feature-rich, is often criticized for its aggressive advertising and bloatware. However, MIUI offers extensive customization options, which some users may prefer.
