AMD Athlon X4 840
AMD Athlon X4 840: A Budget Veteran in 2025
Updated: April 2025
Key Specifications: Kaveri Architecture and Its Legacy
The AMD Athlon X4 840 processor, released in 2014 based on the Kaveri architecture, remains a niche solution for ultra-budget builds. Despite its age, it can still be found in new boxes priced $35–45, making it one of the most affordable 4-core CPUs on the market.
Architecture and Process Technology:
- 28nm process technology: By modern standards, this is outdated (compared to 5nm for Ryzen 8000), which explains the high power consumption per unit of performance.
- 4 cores/4 threads: No support for SMT (Simultaneous Multithreading), so multi-threaded performance is limited.
- Base clock of 3.1 GHz, Turbo Core up to 3.8 GHz: Speed is adequate for basic tasks but falls short compared to modern APUs.
- No integrated graphics: A discrete graphics card is required.
Performance:
- Geekbench 6: 458 (Single-Core), 1156 (Multi-Core). In comparison, the Ryzen 3 3200G (2019) scores around ~1100/3500.
- Real-world scenarios: 4K video playback is possible but stutters; Photoshop CS6 runs, but rendering in Blender 4.0 will take 3–4 times longer than with a Ryzen 5 5500.
Key Features:
- Unlocked Multiplier: The unlocked multiplier allows for overclocking (but the potential is limited by the 28nm process technology).
- Mantle API support: An outdated technology that is only relevant for older games like Battlefield 4.
Compatible Motherboards: FM2+ and Finding Rarities
The FM2+ socket and chipsets A88X, A78, A68H form the basis for the Athlon X4 840. In 2025, new boards are rarely produced, but remnants can be found with Chinese sellers:
- ASUS A88XM-Plus — $60–70 (new units).
- Gigabyte GA-F2A68HM-DS2H — $50–55.
Choosing Tips:
- Ports: Look for models with USB 3.0 and SATA III for SSDs.
- Overclocking: A88X chipsets are better suited for overclocking.
- Compatibility: Some boards support Kaveri APUs with Radeon R7 graphics, but this is irrelevant for the X4 840.
Caution: Many boards on the second-hand market ($20–30) may have swollen capacitors or damaged sockets.
Memory: DDR3 and Its Limitations
The Athlon X4 840 only supports DDR3 (up to 2133 MHz). This is a significant drawback in 2025:
- Cost: 8GB DDR3-1866 costs $25 (new modules), while 16GB costs $45.
- Performance: The bandwidth of DDR3 is 2–3 times lower than DDR5, which impacts FPS in games.
- Advice: Use dual-channel memory (2×8 GB instead of 1×16 GB) for a 10–15% boost in multi-threaded tasks.
Power Supply: 65W TDP Does Not Mean "Any PSU"
The processor itself consumes up to 65W, but considering the graphics card and drives:
- Integrated graphics: Not available – a discrete card is needed. For instance, pairing GTX 1650 (75W) with Athlon X4 840 requires at least a 350W PSU.
- Recommendations:
- For systems with GTX 1660 level GPUs: Corsair CV450 (80+ Bronze, $55).
- For overclocking enthusiasts: be quiet! Pure Power 11 500W ($70).
Important: Cheap PSUs without certification (e.g., $25 Chinese PSU) may "support" the system but have a high risk of failure.
Pros and Cons: Who Is It Relevant For in 2025?
Pros:
- Price: $35–45 for 4 cores.
- Energy Efficiency: 65W compared to 95W for FX-8300.
- Overclocking: Potential gains of up to 15% (up to 4.2 GHz on good cooling).
Cons:
- Outdated platform: No PCIe 4.0, USB-C, NVMe.
- Weak IPC: Falls behind even budget Celeron processors from 2023.
- No support for Windows 12: Officially only works with Windows 10.
Usage Scenarios: Where the X4 840 Still Holds Up
1. Office and Multimedia:
- Google Docs, Excel, 1080p streaming.
- Example: Office build with GT 1030 ($90) and 256 GB SSD ($30) — total cost ~$200.
2. Retro Gaming:
- GTA V on low settings (40–50 FPS with GTX 1050 Ti).
- World of Warcraft: Classic — stable 60 FPS.
3. Servers:
- NAS based on OpenMediaVault (4 cores are sufficient for a 1-gigabit network).
Not suitable for:
- Modern games (Cyberpunk 2077, Alan Wake 2).
- Video editing in DaVinci Resolve.
Comparison with Competitors
1. Intel Celeron G6900 (2023):
- $50–60, 2 cores/2 threads, DDR4.
- Geekbench 6: 980/1850.
- Conclusion: Celeron is faster in single-threaded tasks but lags in multi-threading.
2. AMD Ryzen 3 3200G (2019):
- $80–90, 4 cores/4 threads, Vega 8.
- Geekbench 6: 1100/3500.
- Conclusion: 2–3 times faster but more expensive.
Building Tips
1. Motherboard: Look for A88X with USB 3.0 (ASUS A88XM-Plus).
2. Cooling: The stock cooler is sufficient, but for overclocking, consider the DeepCool Gammaxx 400 ($20).
3. Graphics Card: GTX 1650 or RX 6400 — maximum without bottlenecks.
4. Storage: An SSD is essential (Kingston A400 240 GB — $25).
Conclusion: Who Is the Athlon X4 840 Suitable For in 2025?
This processor is a choice for:
- Budget build enthusiasts: For example, a PC for parents or children.
- Upgrading old systems: If your FM2+ motherboard is still alive.
- Entry-level servers: Low power consumption and 4 cores.
Don’t choose it if you need modern performance. But for $35, it’s a fair option for tasks from the last decade.