We start our benchmarks with the Cinebench R15, as it gives an idea of single and multi-threaded thread performance. High frequency typicallgives performance in single-threaded tests, whereas having good scaling and many cores is where the multi-threaded test wins out.
The Core i7-8700K got the highest score in the chart, in both ST and MT tests, taking advantage of its high frequency, which peaked at the 4.7GHz. In the ST test the Core i7-8700K has an about 7% lead over the Core i7-7700K and also left the the Ryzen 7 1700 behind. With all cores working, AMD's chip closed the gap with the Core i7-8700K.
The Core i5-8400 chip hit the 4.0GHz blind and its reached about the 90% of the performance of the Core I7-7700K in the single core test. In addition, the Core i5-8400 has a lead over the Ryzen 7 1700 in ST.
Video transcoding is a hot topic in performance metrics as more and more content is being created. We tested the CPUs in H264 and HEVC (or H265) encoding using the Handbrake tool and TMPG Video Mastering Works 6 tools.
The Core i7-8700K is about 30-40% faster than the Ryzen 7 1700. In addition, the Core i5-8400 is also faster than Core i7-7700K by a smaller about 4%. Multi-thread performance is the game-changing factor in video encoding so even not the top Coffee Lake-S CPU is fsater than the top Kaby Lake-S CPU: