Redmi K90 Ultra vs Samsung Galaxy A51
The Redmi K90 Ultra (2026) runs on the Qualcomm Snapdragon 8 Elite, while the Samsung Galaxy A51 (2020) runs on the Exynos 9611; launch prices were $420 and $399. By overall MobileRank rating, the Redmi K90 Ultra leads — 73/100 vs 34/100 (a 39-point difference). Key differences: the Redmi K90 Ultra has the bigger battery (8550 mAh vs 4000); the main camera is 50 MP vs 48 MP; the Redmi K90 Ultra is faster in AnTuTu (3,233,695 vs 355,351); the Samsung Galaxy A51 is noticeably lighter (172g vs 227g).
Profile comparison
Category scores
Redmi K90 Ultra
Samsung Galaxy A51
What makes Redmi K90 Ultra better?
- Higher AnTuTu: 3233695 vs 355351
- Better Geekbench Single: 3013 vs 365
- Better Geekbench Multi: 9287 vs 1107
- Bigger battery: 8550 vs 4000 mAh
- Better main camera: 50MP vs 48MP
- Higher refresh rate: 165Hz vs 60Hz
- Higher performance (92/100 vs 25/100)
- Better camera (37/100 vs 36/100)
- Longer battery life (78/100 vs 25/100)
- Better display (94/100 vs 51/100)
What makes Samsung Galaxy A51 better?
- Lighter: 172g vs 227g
- Cheaper at launch: $399 vs $420
- Better portability (77/100 vs 40/100)
Comparison verdict
Comparing the Redmi K90 Ultra vs the Samsung Galaxy A51, the Redmi K90 Ultra scores 39 points higher (73/100 vs 34/100). In the "performance" category, the Redmi K90 Ultra leads (92/100 vs 25/100). In the "battery" category, the Redmi K90 Ultra leads (78/100 vs 25/100). Value score: Redmi K90 Ultra — 72/100, Samsung Galaxy A51 — 0/100; it shows how far a model sits above or below the usual level for its price, and is not part of the overall rating. In the "performance" category, the Redmi K90 Ultra significantly outperforms the Samsung Galaxy A51 (92/100 vs 25/100). In the "display" category, the Redmi K90 Ultra significantly outperforms the Samsung Galaxy A51 (94/100 vs 51/100). In the "camera" category, the Redmi K90 Ultra and the Samsung Galaxy A51 are nearly equal (37/100 vs 36/100). In the "battery" category, the Redmi K90 Ultra significantly outperforms the Samsung Galaxy A51 (78/100 vs 25/100). In the "portability" category, the Samsung Galaxy A51 significantly outperforms the Redmi K90 Ultra (77/100 vs 40/100).
Specs comparison
| Specification | Redmi K90 Ultra | Samsung Galaxy A51 | |
|---|---|---|---|
| Processor | Qualcomm Snapdragon 8 Elite | Exynos 9611 | |
| AnTuTu | 3233695 | 355351 | |
| Geekbench Single | 3013 | 365 | |
| Geekbench Multi | 9287 | 1107 | |
| Display | 6.8" AMOLED | 6.5" AMOLED | |
| Resolution | 1280x2772 | — | |
| Refresh rate | 165 Hz | 60 Hz | |
| Battery | 8550 mAh | 4000 mAh | |
| Charging | 100W | — | |
| Main camera | 50 MP | 48 MP | |
| Ultrawide | 8 MP | 0 MP | |
| Front camera | 20 MP | 32 MP | |
| RAM | 12GB / 16GB | 4GB / 6GB | |
| Storage | 256GB / 512GB | 64GB / 128GB | |
| OS | Android 16 | — | |
| Brightness (peak) | 3500 nits | — | |
| NFC | yes | yes | |
| Protection | IP68/IP69 | — | |
| Dimensions | 162.9×77.9×8.2 mm | 158.5×73.6×7.9 mm | |
| Weight | 227 g | 172 g | |
| Launch price | $420 | $399 |
Camera comparison
Redmi K90 Ultra
- Main: 50MP f/1.7
- Ultrawide: 8MP
- Front: 20MP
Samsung Galaxy A51
- Main: 48MP
- Front: 32MP
Display comparison
Redmi K90 Ultra
- 6.8" AMOLED
- Resolution: 1280x2772
- Refresh rate: 165 Hz
Samsung Galaxy A51
- 6.5" AMOLED
- Refresh rate: 60 Hz
Battery and charging
Redmi K90 Ultra
- 8550 mAh
- Wired: 100W
- No wireless charging
Samsung Galaxy A51
- 4000 mAh
- No wireless charging
Overall performance score
We compared Redmi K90 Ultra and Samsung Galaxy A51, covering their specs and all relevant benchmarks.
Redmi K90 Ultra leads Samsung Galaxy A51 by 810.0% in our overall performance rating.
Benchmarks
Launch prices and where to check today's
Launch price difference: $21. Samsung Galaxy A51 was $21 cheaper at launch.
Detailed category analysis
performance
In the "performance" category, the Redmi K90 Ultra significantly outperforms the Samsung Galaxy A51 (92/100 vs 25/100).
display
In the "display" category, the Redmi K90 Ultra significantly outperforms the Samsung Galaxy A51 (94/100 vs 51/100).
camera
In the "camera" category, the Redmi K90 Ultra and the Samsung Galaxy A51 are nearly equal (37/100 vs 36/100).
battery
In the "battery" category, the Redmi K90 Ultra significantly outperforms the Samsung Galaxy A51 (78/100 vs 25/100).
portability
In the "portability" category, the Samsung Galaxy A51 significantly outperforms the Redmi K90 Ultra (77/100 vs 40/100).
Frequently asked questions
Which is better: the Redmi K90 Ultra or the Samsung Galaxy A51?
The Redmi K90 Ultra significantly outperforms the Samsung Galaxy A51 by 39 points (73/100 vs 34/100).
What is the rating of the Redmi K90 Ultra and the Samsung Galaxy A51?
The Redmi K90 Ultra has a MobileRank rating of 73/100, the Samsung Galaxy A51 — 34/100.
Which is more powerful: the Redmi K90 Ultra or the Samsung Galaxy A51?
The Redmi K90 Ultra leads on performance (92/100 vs 25/100).
Should you choose the Redmi K90 Ultra over the Samsung Galaxy A51?
The Redmi K90 Ultra is a better fit for gamers and power users, those who care about battery life.