Samsung Galaxy A51 Vs S9 Is The Newer Model Really Worth It

When Samsung released the Galaxy S9 in 2018, it was a flagship powerhouse—flagship display, top-tier camera, and premium build. Fast forward to 2020, and the Galaxy A51 arrived as a mid-range contender with modern features at a fraction of the price. But for users still holding onto their Galaxy S9, the question arises: Is upgrading to the A51 actually worthwhile?

The answer isn’t straightforward. While the A51 brings newer technology and improved longevity in some areas, the S9 still holds its ground in others. Let’s break down the key differences and see where each phone excels—and whether the newer model truly outshines its predecessor.

Design and Build Quality

The Galaxy S9 was designed to impress. With its glass back, aluminum frame, and IP68 water resistance, it felt like a premium device in hand. Its compact 5.8-inch display made it easy to use one-handed, and the curved edges gave it a sleek, futuristic look. Even years later, the S9’s design remains elegant.

In contrast, the Galaxy A51 opts for a more utilitarian approach. It uses plastic for both the frame and back, which keeps costs low but sacrifices that high-end feel. While it has a larger 6.5-inch Super AMOLED display, the bezels are thicker, and there’s no official water resistance rating. The flat screen improves usability but lacks the visual flair of the S9’s curved display.

That said, the A51’s larger size accommodates a bigger battery and a more immersive viewing experience, which many users now prioritize over compactness.

Tip: If you value durability and a premium feel, consider using a protective case on the A51 to compensate for its plastic build.

Display Comparison: Size vs. Sharpness

Both phones feature Super AMOLED panels, known for vibrant colors and deep blacks. However, the implementation differs.

The S9 has a 5.8-inch QHD+ (1440 x 2960) display with a pixel density of 570 PPI. This results in incredibly sharp visuals, smooth text rendering, and excellent outdoor visibility. The curved edges enhance immersion but can cause glare or accidental touches.

The A51, while larger at 6.5 inches, uses a Full HD+ resolution (1080 x 2400) with a lower pixel density of 405 PPI. While still crisp for most users, the difference in sharpness becomes noticeable when viewing high-resolution content side by side.

However, the A51 introduces an in-display fingerprint sensor—a feature absent on the S9, which uses a rear-mounted sensor. This modern convenience adds to the seamless, edge-to-edge design.

“Display quality isn’t just about resolution—it’s about how the screen fits your usage. For media consumption, size often trumps sharpness.” — David Lin, Mobile UX Analyst

Performance and Software Longevity

This is where the gap widens significantly. The Galaxy S9 launched with the Exynos 9810 or Snapdragon 845 (depending on region), paired with 4GB of RAM. At the time, this ensured buttery-smooth performance across apps and games.

By today’s standards, however, the S9 struggles with heavier multitasking and newer Android updates. While it received updates up to Android 10, it no longer supports major OS upgrades or monthly security patches, leaving it vulnerable and less optimized.

The A51, powered by the Exynos 9611 (or occasionally the 9609), comes with 4GB or 6GB of RAM and runs Android 10 out of the box, upgradable to Android 13. Though the chipset is mid-range and not as powerful as the S9’s original processor in raw benchmarks, it handles daily tasks efficiently thanks to better software optimization and newer architecture.

More importantly, the A51 continues to receive security updates and is compatible with current apps and services—a crucial advantage for long-term usability.

Real-World Example: Daily Use After Three Years

Consider Maria, who used her Galaxy S9 from 2018 to 2021. By her third year, she noticed increasing lag when opening Instagram, delays in app switching, and compatibility issues with banking apps that dropped support for older Android versions. She upgraded to the A51 and immediately saw improvements: faster app launches, smoother navigation, and reliable access to all services—even if the processor wasn’t technically “faster” in synthetic tests.

This illustrates a key point: real-world performance depends on software support and optimization, not just hardware specs.

Camera Capabilities: One Lens vs. Four

The S9 featured a single 12MP rear camera with variable aperture (f/1.5–f/2.4), a rare feature even today. It adapted to lighting conditions automatically, producing excellent low-light photos and rich dynamic range. Its optical image stabilization and fast autofocus made it a favorite among mobile photographers.

The A51 counters with a quad-camera setup: 48MP main, 12MP ultra-wide, 5MP macro, and 5MP depth sensor. On paper, this seems superior. In practice, the A51 relies heavily on software processing. While daylight shots are detailed, low-light performance lags behind the S9 due to smaller pixel size and lack of OIS.

However, the ultra-wide lens adds creative flexibility, and the dedicated macro and depth sensors improve portrait mode accuracy and close-up photography—features the S9 simply doesn’t offer.

Feature	Galaxy S9	Galaxy A51
Main Camera	12MP, f/1.5–f/2.4, OIS	48MP, f/2.0, no OIS
Additional Lenses	None	Ultra-wide, Macro, Depth
Front Camera	8MP, f/1.7	32MP, f/2.2
Low-Light Performance	Excellent	Fair (software-enhanced)
Versatility	Limited to one lens	High (multiple shooting modes)

Battery Life and Charging

The Galaxy S9 packs a 3,000mAh battery—modest even for its time. With moderate use, it lasted a full day, but heavy usage required midday charging. It supports fast charging (15W) and wireless charging, adding convenience.

The A51 steps up with a 4,000mAh battery—33% larger capacity. Combined with a more power-efficient processor and software optimizations, it easily lasts a full day and often stretches into a second. However, it only supports 15W fast charging and lacks wireless charging.

For users who hate hunting for outlets, the A51’s battery is a clear win. But those who value wireless charging may miss that feature.

Tip: Enable adaptive battery settings on the A51 to extend charge cycles and reduce background drain.

Is the A51 Worth Upgrading To?

The decision hinges on your priorities:

• If you want longer software support, better battery life, and modern features like an in-display fingerprint sensor and ultra-wide camera, the A51 is a strong upgrade.
• If you prioritize premium materials, superior low-light photography, and a more compact form factor, the S9 may still serve you well—especially if you’re not experiencing performance issues.

For most users, especially those facing slowdowns or app compatibility problems, the A51 offers tangible benefits despite its lower-tier build. It represents a shift in Samsung’s strategy: delivering key innovations to the mid-range market, making flagship-level features accessible.

Checklist: Should You Upgrade?

1. ✔️ Is your S9 slowing down with everyday apps?
2. ✔️ Are you missing security updates or unable to install new apps?
3. ✔️ Do you want better battery life for commuting or travel?
4. ✔️ Would you benefit from an ultra-wide camera or in-display fingerprint sensor?
5. ✔️ Can you accept a plastic build and slightly lower display sharpness?

If you answered yes to three or more, the A51 is likely a worthwhile upgrade.

Frequently Asked Questions

Can the Galaxy A51 run the same apps as the S9?

Yes, and more. The A51 supports newer Android versions and receives regular updates, ensuring compatibility with current apps. Some newer apps may no longer support the S9’s outdated Android version.

Does the S9 have better speakers than the A51?

Yes. The S9 features stereo speakers tuned by AKG with one speaker at the bottom and another integrated into the earpiece. The A51 has a single bottom-firing speaker, resulting in less immersive audio.

Is the A51 waterproof?

No. Unlike the S9’s IP68 rating, the A51 has no official water or dust resistance. Avoid exposure to moisture and consider a rugged case if needed.

Final Verdict

The Galaxy A51 isn’t objectively “better” than the S9 in every way—but it is more suited to today’s mobile ecosystem. It trades flagship materials for future-proof software, extended battery life, and versatile camera options. For users clinging to a four-year-old phone, that trade-off often makes sense.

The S9 was a product of its time: sleek, powerful, and ahead of the curve. The A51 reflects today’s reality: practical, connected, and built for longevity in a world that moves fast.

If your S9 still performs well and you don’t need new features, there’s no urgent reason to switch. But if you’re feeling the limitations of age—slow apps, short battery, outdated software—the A51 offers a compelling, affordable step forward.

🚀 Ready to make the leap? Evaluate your current pain points and consider what matters most—premium feel or modern functionality. Your next phone should work for your life, not just your preferences.