Intel's Core processors were long overdue for an infusion of extra execution resources. Two more cores help the Core i5-8600K put serious distance between Kaby Lake in threaded workloads, while aggressive Turbo Boost binning ensures you don't lose performance at any given utilization level. In fact, the six-core -8600K generally offers higher clocks than the -7600K in real-world tasks, despite Intel's lower base frequency specification.
The Core i5-8600K benefits gaming performance in a quantifiable way. We use a geometric mean of 99th percentile frame times, a good indicator of smoothness, converted into an FPS measurement. Five of the games we test were released in 2016, and five are older (2014/2015). Extra cores could enable more performance as software evolves, so we also include a chart with newer games that thoroughly utilize available host processing resources. We also have price-to-performance charts that include extra platform costs. For the models that don't come with a bundled cooler, we add an extra $25 for a basic heat sink. We also add $20 if overclocking requires a more expensive motherboard (as is the case for Z370).
Officially, Core i5-8600K sells for $15 more than its Kaby Lake predecessor (though street pricing currently has it +$40). The -8600K does, however, deliver more performance in most games. It even matches the Core i7-7700K, typically. AMD's Ryzen 5 1600X offers solid performance for enthusiasts on a budget, but it tends to trail the stock Core i5. And that's after overclocking.
Ryzen 7 1700 might be a more compelling option thanks to its eight cores and 16 threads, particularly if you run a lot of rendering/encoding tasks. A price point around $300 comes awful close to Core i5-8600K's current $280. And when you factor in lower-cost AMD motherboards and a bundled Wraith Spire heat sink/fan, an unlocked Coffee Lake chip quickly becomes more expensive. After all, it doesn't include cooling at all, while overclocking necessitates a premium Z370-based platform.
Overall, Intel's Core i5-8600K offers balanced performance in a wide range of workloads. Right now, availability is an issue. Provided you can find one, though, the -8600K delivers an unmatched gaming experience at its price.
For a bit of perspective, Core i5-8600K often provides similar gaming frame rates as the previous-gen Core i7-7700K, and it's incredibly competitive in productivity workloads. However, you can buy it for $60 less. That's an incredible jump. We stop short of saying Core i5-8600K represents the best gaming value because we haven't reviewed the multiplier-locked models yet. But -8600K certainly provides the best gaming value of the processors we've tested so far. That means you can build a gaming PC with GeForce GTX 1080 Ti or Radeon RX Vega 64 and not worry about host processing bottlenecks.
The Core i5-8600K also wields more horsepower for heavy-lifting, improving the results you'll see in demanding productivity workloads. AMD does well in that category as well though, so keep your eyes out for deals!
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