Intel Core i5-8420
Intel Core i5-8420: Review and Recommendations for PC Build in 2025
Architecture: Coffee Lake | Process Technology: 14 nm | Cores/Threads: 6/6 | L3 Cache: 9 MB | TDP: 65 W
1. Key Features: Balance Between Past and Future
The Intel Core i5-8420 processor belongs to the Coffee Lake line released in the late 2010s. Despite the age of its architecture, it remains popular in budget builds thanks to its 6 physical cores and stable operation at a base frequency of 2.9 GHz (Turbo Boost up to 4.1 GHz). The 14 nm process technology, although outdated by 2025, ensures moderate power consumption (TDP 65 W).
Key Features:
- 6 Cores without Hyper-Threading: Suitable for tasks optimized for multi-threading but lags behind modern CPUs with SMT (e.g., AMD Ryzen 5 5600).
- Intel UHD Graphics 630: Integrated graphics for office tasks and light gaming like CS:GO on low settings.
- Intel Technologies: Support for Turbo Boost 2.0, Optane Memory, and AES hardware acceleration.
Practical Example: In 2025, the i5-8420 is often used in office PCs for working with Excel and browsers—the processor does not overheat even under load for 6–8 hours.
2. Compatible Motherboards: Sockets and Chipsets
The processor uses the LGA 1151 v2 socket compatible with 300-series chipsets:
- Z370/H370: For overclocking (if the CPU is unlocked) and support for PCIe 3.0 x16.
- B360/H310: Budget boards without overclocking but with basic features (up to 64 GB DDR4).
Recommendations:
- ASUS Prime B360M-A: A reliable board priced at $70–90 with M.2 NVMe support.
- Gigabyte Z370 HD3: For enthusiasts wanting to connect two graphics cards (though this is rare in 2025).
Important: New motherboards for LGA 1151 v2 are no longer produced, but they can be found as New Old Stock (NOS) at prices between $80–150.
3. Memory Support: DDR4 as the Standard
The i5-8420 works only with DDR4 (official support up to 2666 MHz). Trying to install DDR5 will lead to incompatibility—the memory controller of the processor is not designed for new standards.
Recommended Modules:
- 2×8 GB DDR4-2666 CL16: Optimal for gaming and multitasking.
- Single-channel mode: Avoid—can lead to loss of up to 30% performance in games.
Example: In a build with DDR4-3200, memory will operate at 2666 MHz, but low timings (e.g., CL14) can enhance system responsiveness.
4. Power Supply Units: Power Calculation
With a TDP of 65 W and no overclocking, a power supply of 400–500 W is sufficient, especially if using a graphics card like the NVIDIA GTX 1660 Super (TDP 125 W).
Recommendations:
- Be Quiet! System Power 10 450W (80+ Bronze): A reliable option priced at $50–60.
- If planning an upgrade: Choose a PSU with 600–650 W and an 80+ Gold rating (for example, Corsair RM650x).
Tip: Don't skimp on the PSU—a poor-quality model can damage components.
5. Pros and Cons of the Processor
Pros:
- Energy Efficiency: Consumes less power than modern 6-core CPUs.
- Price: New units in 2025 cost $120–150.
- Compatibility: Supports Windows 10/11 and Linux.
Cons:
- No Hyper-Threading: Falls short in multi-threading tasks compared to Ryzen 5 5500 (6/12).
- Outdated Process Technology: 14 nm vs. 7 nm competitors.
- No PCIe 4.0/5.0: Limitation for high-speed NVMe storage.
6. Use Cases
- Gaming: Fortnite, Apex Legends at medium settings in Full HD (with a graphics card like RTX 3050).
- Work Tasks: Office applications, programming, rendering in Blender (but slower than Ryzen).
- Multimedia: Streaming in 720p (without serious encoding).
Example: Students often choose the i5-8420 for studying—it has enough power for Zoom, a browser with 20+ tabs, and light video editing.
7. Comparison to Competitors
- AMD Ryzen 5 5500 (6/12, 7 nm): 25–30% faster in multi-threading tasks but pricier ($160–180).
- Intel Core i3-12100F (4/8, 10 nm): Better in single-core performance but has fewer cores.
Conclusion: The i5-8420 only wins in price and power consumption.
8. Practical Building Tips
- Cooling: The stock cooler is sufficient, but for quieter operation, consider the DeepCool Gammaxx 400 ($20).
- Storage: An NVMe SSD is essential (e.g., Kingston NV2 500 GB for $35).
- Graphics Card: No higher than RTX 3060/RX 6600 to avoid a bottleneck.
9. Final Conclusion: Who Should Consider the i5-8420?
This processor is the choice for those who:
- Are building a PC for office or study with a budget up to $500.
- Are looking for a temporary solution before moving to a modern platform.
- Value stability and low power consumption.
Alternative: If budget allows, it’s better to opt for Ryzen 5 5500 or Intel Core i5-12400F—as they are more relevant in 2025.
Prices are listed as of April 2025 for new devices.