Looks like there is some performance problem with yescript16 implementation on coffee-lake cpus
Intel i5 4440 (stock 3.3GHz) @4 threads generates ~600h/s
Intel i7 5820k (no overclock, 3.6GHz) @12 threads generates ~1200h/s in pool and up to 1400 in solo mining (6 threads generate little less) with both cpuminer-opt (3.7.6 and 3.7.7v2) under windows64 and under ubuntu64
Intel i7 8700k (stock 4.3GHz) @12 threads generates only 950h/s (both pool and solo), overclocking to 5Ghz (50x100) with cache overclock to 4.6Ghz (stock is 4.2) gives no profit, even more usually performance degrade (power limit disabled, core temperatures are ~75C so no throttling involved), 1-2-3-4-5-6 threads gives less results, overclocking bus to 130Mhz (also with ram) gives no result - maximum is about 950h/s
Even more funny - on stock frequency, switching from AVX to SSE2 gives some performance boost from 950 to 1000-1050h/s

I understand that 8700k lacks quad-channel RAM and has little bit less L3 cache (12 vs 15Mb), compared to 5820, but bottleneck is obviously something different because ram overclock gives no result (so double channel is not a problem, we should see performance boost when overclocking bus and ram) and cache is also not a problem (25% cache is gone but we gain >30% frequency bonus (when overclocked) so our smaller cache works at higher speeds together with cpu cores - we can put less but more frequent and calc it in less time - ) also, compared to 4440, if cache was a bottleneck, we have twice more (12 vs 6Mb), taking in mind much higher speed and optimized pipelane, if cache only matters, we should have 2x gain, compared to 4440

I hope for a fix