Intel Core i5-8400 vs Intel Core i5-9600K vs Intel Core i9-9900KS

Intel Core i5-8400

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.

Intel Core i5-9600K

The Intel Core i5-9600K is a high end desktop processor based on the Coffee Lake architecture. It offers an open multiplicator for easy overclocking and integrates 6 cores (no Hyperthreading therefore also 6 threads) clocked at 3.7 - 4.6 GHz and it needs a new Z390 based mainboard. It is manufactured in the second iteration of the improved 14nm process (14nm++).

Compared to the older Core i5-8600K, the 9600K offers about 10 to 15% higher performance. As the CPU still offers 6 cores and threads, the improvements are mostly due to the higher clock speeds. As a fast mid range desktop CPU, the i5-9600K is suited even for very demanding applications and perfect for 3D gaming.

The integrated Intel UHD Graphics 630 graphics card is clocked at up to 1.15 GHz and offers no advantage compared to previous generations. As it is a very low end GPU, only some low demanding games like Hearthstone can be played with it (see GPU page for benchmarks).

Intel specifies the TDP at 95 Watt, so if the CPU is used in laptops a big and chunky cooling system is needed to avoid throttling and lower clock speeds under sustained loads. When overclocking the CPU, the power consumption can easily rise up to 150 Watt and higher.

Intel Core i9-9900KS

The Intel Core i9-9900KS is a high end desktop processor that includes 8 cores based on the Coffee Lake architecture. It is the fastest Coffee Lake CPU in 2019 and compared to the similar named i9-9900K, the KS offers an all core Turbo of 5 GHz. All cores can clock between 4 GHz and 5 GHz and thanks to Hyperthreading / SMT 16 threads can be executed in parallel. The CPU is still manufactured in the mature 14 nm process (14nm++). Thanks to the open multiplicator, the CPU is rather easy to overclock (if a Z390 based mainboard is used).

With good cooling, the i9-9900KS can be around 10% faster than the older Intel Core i9-9900K (thanks to the 5 GHz all core Turbo). Compare to the old Core i7-8700K, the 9900KS is even 45% faster. Especially for gaming, the 9900KS is currently the fastest option available. The fast Ryzen and Threadripper CPUs from AMD however offer a better multithreaded performance.

The integrated GPU is called Intel UHD Graphics 630 and clocks with up to 1.2 GHz. It is not suited for demanding 3D games and located in the low end.

The TDP is raised to 127 Watt for the additional performance, therefore a good CPU cooler is needed. When overclocking the CPU, more than 200 Watt can be reached unter load.