Intel Core i5-8420

The Intel Core i5-8420 is a 6-core, 6-thread desktop processor built on Intel's 14 nm Coffee Lake architecture. It operates at a base clock of 2.90 GHz and a boost clock of 4.10 GHz, with a 65 W TDP. The chip supports DDR4 memory in a dual-channel configuration, integrates UHD Graphics 630, and uses Intel Socket 1151. Released in 2018, it is now end-of-life, with a locked multiplier and a part number of SR3X4.

Benchmark Performance

The i5-8420 holds a 50th percentile ranking among all CPUs in the database, placing it exactly at the median of the performance distribution. This means half of the CPUs in the database are faster, and half are slower. The benchmark list for this processor is empty, and no nearest rivals are provided, so direct percentage comparisons against specific competitors are not available from the data. The absence of individual scores forces reliance on the percentile as the sole quantitative performance indicator. With 6 cores and 6 threads, the processor offers a symmetric core-to-thread ratio, indicating that simultaneous multithreading is not implemented. The 9 MB of shared L3 cache, along with 64 KB of L1 and 256 KB of L2 per core, forms a moderate cache hierarchy that supports data-intensive workloads. The 4.10 GHz boost clock is the maximum frequency the chip can achieve under light single-core load, while the 2.90 GHz base clock represents the sustained frequency under full multi-core stress. The 50th percentile ranking suggests that the i5-8420 delivers typical mainstream performance—adequate for everyday tasks but not exceptional in either single-threaded or multi-threaded scenarios. The lack of benchmark entries means that the percentile is likely derived from historical data or extrapolation, but the database records it as a definitive metric. The processor's 6-core layout, without hyper-threading, positions it as a conventional mid-range part that can handle common productivity workloads without hitting hard performance walls. The 14 nm process node, while older than more recent nodes, still allows for competitive clock speeds relative to the power envelope. The integrated UHD Graphics 630 adds a modest GPU capability, which can offload some display tasks but does not contribute to compute benchmarks. Overall, the data indicates a balanced, if unremarkable, performance profile that aligns with its median ranking.

Power and Thermals

The i5-8420 has a TDP of 65 W, classifying it as a low-to-mid power desktop processor. This power envelope is common for mainstream CPUs and implies that a standard cooling solution—such as a compact air cooler or a low-profile cooler—can handle the thermal output. The 65 W figure covers the entire package, including the integrated UHD Graphics 630, which shares the same thermal budget. The 14 nm process node is a mature manufacturing technology that balances performance and efficiency, contributing to the modest power draw. The processor's locked multiplier prevents user-initiated overclocking, meaning the TDP cannot be increased beyond its rated specification through voltage or frequency adjustments. This also means that power consumption remains predictable and within the designed limits. The end-of-life status suggests that thermal solutions designed for Socket 1151 are still available, but newer coolers may not be specifically optimized for this chip. The 65 W TDP allows for compact system builds, such as small form factor desktops or all-in-one units, where space and airflow are limited. The integrated graphics add a small amount of heat, but the total thermal load is manageable with a basic cooling setup. The 14 nm process has been widely used across Intel's Coffee Lake generation, and its thermal characteristics are well understood. The processor's power efficiency is further indicated by its dual-channel memory support, which reduces memory-related power overhead compared to quad-channel designs. The absence of ECC memory support (eccMemory: false) simplifies the memory power delivery, as no error-correcting logic is required. Overall, the 65 W TDP makes the i5-8420 an easy part to cool, even in constrained environments.

Single-Thread vs Multi-Thread Behavior

The i5-8420's 6 cores and 6 threads mean that each core handles exactly one thread, with no hyper-threading to increase parallelism. This configuration limits multi-threaded performance compared to processors with higher thread counts, but it also reduces scheduling complexity and power overhead. For single-threaded workloads, the 4.10 GHz boost clock is the maximum attainable frequency, which is beneficial for applications that rely on high clock speeds, such as legacy games, spreadsheet calculations, and some database queries. The base clock of 2.90 GHz is the sustained frequency when all cores are active, and the difference between base and boost (1.20 GHz) is significant, indicating that the processor can ramp up frequency substantially when only a few cores are utilized. This behavior is typical of Intel's Turbo Boost technology, though the exact mechanism is not specified in the data. The 9 MB shared L3 cache helps reduce memory latency for frequently accessed data, aiding both single- and multi-threaded performance. The lack of an unlocked multiplier means users cannot manually increase the boost clock beyond its rated 4.10 GHz, so single-thread performance is capped at the factory setting. In multi-threaded scenarios, the 6-thread limit becomes a bottleneck for heavily parallel workloads such as video rendering, 3D simulation, or large-scale compilation. The processor's thread count equals its core count, so there is no overhead from thread scheduling across virtual cores. This design favors consistent performance in lightly threaded applications, where the boost clock can be maintained. The 64 KB L1 and 256 KB L2 per core provide fast access to working sets, while the shared L3 cache (9 MB) facilitates data sharing between cores. The memory bandwidth of 42.7 GB/s is adequate for dual-channel DDR4, though it may limit performance in memory-bound multi-threaded tasks. Overall, the i5-8420 is better suited for single-threaded or lightly threaded workloads, while multi-threaded performance is constrained by the 6-thread ceiling.

Platform and Compatibility

The i5-8420 uses Intel Socket 1151, a mainstream desktop socket that was widely used across Intel's 8th and 9th generation processors. The chip supports DDR4 memory with a dual-channel bus, providing a theoretical memory bandwidth of 42.7 GB/s. The memory controller does not support ECC memory, as indicated by the eccMemory: false field. For expansion, the processor provides PCIe Gen 3 with 16 lanes (CPU only), which can be used for a discrete graphics card or other high-bandwidth devices. The integrated UHD Graphics 630 offers display output without requiring a separate GPU, making the processor suitable for basic systems. The processor is based on the Coffee Lake architecture and was released on 2018-08-31, with a production status of end-of-life. This means Intel has discontinued the part, and availability is limited to existing inventory or the used market. The 14 nm process node is consistent with other Coffee Lake CPUs, and the socket 1151 is compatible with motherboards that support this architecture, though specific chipset compatibility is not listed in the data. The processor's part number is SR3X4, which can be used for identification. The memory support is limited to DDR4, with no mention of DDR3 or other types. The dual-channel configuration requires matching memory modules to achieve optimal bandwidth. The 16 PCIe Gen 3 lanes are sufficient for a single high-end graphics card or multiple lower-bandwidth cards, but the lack of additional chipset lanes means that storage and other peripherals rely on the motherboard's chipset. The integrated graphics use the same memory bandwidth as the CPU, which can impact performance if the iGPU is heavily used. The end-of-life status implies that driver updates and BIOS support may be limited in the future, though the processor remains functional in existing systems. The socket 1151 platform is mature, and many motherboards from the 300-series chipsets are available, but the data does not specify which ones are compatible. Overall, the platform is standard for its generation, offering a balance of features for mainstream desktop builds.

Who Should Consider It

The i5-8420 is positioned for users who need a dependable desktop processor for everyday computing tasks, as indicated by its 50th percentile performance ranking. The 6-core/6-thread configuration handles common productivity workloads such as web browsing, document editing, email, and media playback without strain. The integrated UHD Graphics 630 eliminates the need for a discrete GPU in basic builds, making the processor suitable for office systems, home theater PCs, or lightweight general-purpose machines. The 65 W TDP allows for compact and quiet system designs, which is appealing for small form factor cases or environments where noise is a concern. The locked multiplier means that overclocking is not possible, so enthusiasts who wish to push performance beyond stock settings should look elsewhere. The lack of hyper-threading limits multi-threaded performance, so users who frequently run heavily parallel applications—such as video editing, 3D rendering, or scientific simulations—may find the 6-thread ceiling restrictive. For single-threaded tasks, the 4.10 GHz boost clock provides solid responsiveness, making the chip adequate for legacy games that do not utilize many cores. The 42.7 GB/s memory bandwidth and 16 PCIe Gen 3 lanes are sufficient for a single mainstream graphics card, allowing for light gaming or GPU-accelerated workloads. The end-of-life status means that buyers should consider the availability of replacement parts and long-term support, though the processor remains functional for many years. The absence of ECC memory support rules out server or workstation use where error correction is required. Overall, the i5-8420 is a reasonable choice for budget-conscious builders who prioritize simplicity and low power consumption over raw multi-threaded performance. Its median percentile ranking ensures that it will not be a bottleneck for typical desktop use, but users with demanding workloads should consider higher-tier alternatives, even though direct comparisons are not listed in the data.