The Intel Core i5-8400 is a mid-range 6-core CPU. The processor belongs to the Coffee Lake generation and was presented in September 2017. It does not support Hyper-Threading, which means it can run six threads simultaneously. The base clock rate is 2.8 GHz and the CPU can speed up to 4.0 GHz under high load. Despite belonging to the new generation of CPUs, the Core i5-8400 is manufactured in an improved 14nm process.
Performance
The processor offers a strong performance increase compared to the Core i5-7400 due to its two additional cores. Single-core performance has not improved significantly compared to its Kaby Lake predecessor. As a mid-range model, the Core i5-8400 should be suitable for demanding games and programs.
Graphics
The integrated Intel UHD Graphics 630 iGPU is supposed to offer higher performance as its clock rate has been increased by 50 MHz. The build is identical to that of the Intel HD Graphics 630. We do expect a performance improvement, but as a low-end solution it will probably only display current games smoothly at reduced details - if at all.
Power Consumption
Intel specifies the TDP with 65 watts. Therefore, well-dimensioned cooling systems should easily manage to deal with the created heat. We expect increased efficiency due to the higher performance.