Intel Core i7-4790K vs Intel Core i5-8400

The Intel Core i7-4790K (Devils Canyon S), introduced in the second quarter of 2014, was a high-end processor for enthusiasts and overclockers, manufactured using a 22 nm process with four cores and eight threads.

The Intel Core i5-8400 (Coffee Lake S), released in late 2017 for the mainstream market and gamers, uses the finer 14 nm process and offers six physical cores without Hyper-Threading.

Both support PCIe 3.0. In terms of performance, the Intel Core i5-8400 shows noticeably better performance in some single-core benchmarks thanks to its newer architecture. In multi-core tasks, the Intel Core i5-8400, with its six cores, can match or slightly surpass the Intel Core i7-4790K in many scenarios, despite the latter's eight threads.

For gaming, the Intel Core i5-8400 is superior in most titles due to higher IPC values. Regarding energy efficiency, the Intel Core i5-8400 with a TDP of 65W is more economical than the Intel Core i7-4790K with 88W. The Intel Core i7-4790K features 8 MB L3 cache and 26 GB/s memory bandwidth (Intel HD Graphics 4600), while the Intel Core i5-8400 offers 9 MB L3 cache and 43 GB/s memory bandwidth (Intel UHD Graphics 630).

Currently, both processors are only available on the used market. The Intel Core i7-4790K is interesting for applications with high clock speed requirements and overclocking. However, the Intel Core i5-8400 offers more modern, energy-efficient, and superior performance in most general and gaming applications, making it the better choice for contemporary systems.