Tom's Hardware Verdict
The Core i5-9600K is an iterative update over the previous-gen model. But if you're shopping for a new processor, it does provide enough of a performance improvement to merit attention. The processor clearly provides the best performance for gaming at its price point, though AMD alternatives are enticing if you're more interested in productivity applications.
Pros
- +
Single-threaded performance
- +
Gaming performance
- +
Unlocked multiplier for overclocking
Cons
- -
No bundled cooler
- -
Requires Z-series motherboard to overclock
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The Core i5 Doldrums
It used to be that Core i5 processors represented the best choice for mainstream users looking for value-oriented pricing, high performance, and modest power consumption. But now, fast Ryzen 5 CPUs often prove superior. Intel did increase the core count of its Coffee Lake-based Core i5s by 50 percent to grapple with AMD's first-gen Ryzen 5 chips. However, the latest round of Ryzen 5 models is even faster, particularly in threaded workloads, as you can see in our CPU Benchmark Hierarchy.
Intel's ninth-gen Core i7 and Core i9 processors come with more cores, too. Unfortunately, the Core i5-9600K we're reviewing today does not. It includes the same six cores as its predecessor, along with a price tag that lands between Ryzen 5 2600X and Ryzen 7 2700. Worse, both competing CPUs are bundled with coolers, while Intel makes you buy your own.
The story isn't all bad for Intel. It did switch to a solder-based thermal interface material between its die and heat spreader, enabling higher multi-core Turbo Boost frequencies. But those incremental improvements are hardly earth-shattering.
Choosing between a Core i5-9600K and Ryzen presents the same conundrum we've faced in the past: it depends on the type of software you run most frequently. If you're a gamer who doesn't really venture beyond 1920x1080, Intel's Core i5-9600K is the chip for you. But if a majority of your workloads are threaded in nature, including content creation and productivity, a powerful Ryzen gets you more performance at a competitive price.
AMD has also launched its Ryzen 3000-series processors. The updated Ryzen line-up employs a smaller 7nm process that should confer power and price benefits. It'll also wield the new Zen 2 microarchitecture, which is expected to boost performance while Intel remains mired in a derivative of the seven-year-old Skylake design. These chips have now taken our Best CPUs list by storm, so be sure to head there for a list of the latest leading processors.
Intel Core i5-9600K
The ~$263 Core i5-9600K lands between the $299 Ryzen 7 2700 and $225 Ryzen 5 2600X. Inexplicably, Intel raised the -9600K's price by $5 compared to its previous-gen Core i5-8600K.
| Row 0 - Cell 0 | Core i9-9900K | Core i7-9700K | Core i5-9600K |
| Architecture | Coffee Lake | Coffee Lake | Coffee Lake |
| Socket | 1151 | 1151 | 1151 |
| Cores / Threads | 8 / 16 | 8 / 8 | 6 / 6 |
| Base Frequency (GHz) | 3.6 | 3.6 | 3.7 |
| Boost Frequency ( Active Cores - GHz) | 1-2 Cores - 5.0, 4 Cores - 4.8, 8 Cores - 4.7 | 1 Core - 4.9, 2 Core 4.8, 4 Core 4.7, 8 Core 4.6 | 1 Core - 4.6, 2 Core - 4.5, 4 Core 4.4, 6 Core 4.3 |
| L3 Cache | 16MB | 12MB | 9MB |
| Process | 14nm++ | 14nm++ | 14nm++ |
| TDP | 95W | 95W | 95W |
| Memory Speed | DDR4-2666 | DDR4-2666 | DDR4-2666 |
| Memory Controller | Dual-Channel | Dual-Channel | Dual-Channel |
| PCIe Lanes | x16 | x16 | x16 |
| Integrated UHD Graphics GT2 (Base/Boost MHz) | 350 / 1200 | 350 / 1200 | 350 / 1150 |
| Recommended Customer Pricing | $488 - $499 | $374 - $385 | $262 - $263 |
Intel manufactures the -9600K on its 14nm++ process. In addition to six execution cores (without Hyper-Threading technology), the chip includes an integrated UHD 630 graphics engine, sports unlocked ratio multipliers for easy overclocking, and supports two channels of DDR4-2666 memory. Like the Core i5-8600K that preceded it, the -9600K comes equipped with 9MB of L3 cache and a 95W thermal design power rating.
| Active Cores | Base | 1 Core | 2 Cores | 3 Cores | 4 Cores | 5 Cores | 6 Cores |
| Core i5-9600K (GHz) | 3.7 | 4.6 | 4.5 | 4.4 | 4.4 | 4.3 | 4.3 |
| Core i5-8600K (GHz) | 3.6 | 4.3 | 4.2 | 4.2 | 4.2 | 4.1 | 4.1 |
Intel does dial up the -9600K's Turbo Boost frequencies quite a bit, though. Solder-based thermal interface material improves heat transfer, facilitating higher frequencies whether you're using one core or all six. A base clock rate of 3.7 GHz already represents a 100 MHz improvement over the Core i5-8600K frequency floor, and you get as much as a 300 MHz speed-up when multiple cores are utilized.
We didn't see the need for extreme cooling with Intel's Core i5-9600K, even during our overclocking efforts. The processor held a steady 80°C under five hours of Prime95 optimized for AVX instructions, and ~64°C during a series of non-AVX tasks. Granted, we did use a beefy Corsair H115i cranking away at full speed. But you shouldn't have any trouble cooling the processor at stock settings. Overclocking is fine with a capable closed-loop liquid cooler.
| Model | Cores / Threads | Base Frequency | Boost Frequency | Memory Support | PCIe Lanes | Cache | TDP | Price |
| Core i9-9900K | 8 / 16 | 3.6 GHz | 5 GHz (1 / 2 Core)4.8 GHz (4 Core)4.7 GHz (6 / 8 Core) | DDR4-2666 | 16 | 16MB | 95W | $488 |
| Ryzen 7 2700X | 8 / 16 | 3.7 GHz | 4.3 GHz | DDR4-2966 | 16 + 4 (NVMe) | 16MB | 105W | $329 |
| Core i7-9700K | 8 / 8 | 3.6 GHz | 4.9 GHz (1 Core)4.8 GHz (2 Core)4.7 GHz (4 Core)4.6 GHz (6 / 8 Core) | DDR4-2666 | 16 | 12MB | 95W | $374 |
| Core i7-8086K | 6 / 12 | 4.0 GHz | 5.0 GHz | DDR4-2666 | 16 | 12MB | 95W | $425 |
| Core i7-8700K | 6 / 12 | 3.7 GHz | 4.7 GHz | DDR4-2666 | 16 | 12MB | 95W | $330 |
| Ryzen 7 2700 | 8 / 16 | 3.2 GHz | 4.1 GHz | DDR4-2966 | 16 + 4 (NVMe) | 16MB | 95W | $299 |
| Core i5-9600K | 6 / 6 | 3.7 GHz | 4.6 GHz (1 Core)4.5 GHz (2 Core)4.4 GHz (4 Core)4.3 GHz (6 Core) | DDR4-2666 | 16 | 9MB | 95W | $262 |
| Core i5-8600K | 6 / 6 | 3.6 GHz | 4.3 GHz | DDR4-2666 | 16 | 9MB | 95W | $279 |
| Ryzen 5 2600X | 6 / 12 | 3.6 GHz | 4.2 GHz | DDR4-2966 | 16 + 4 (NVMe) | 16MB | 65W | $225 |
| Ryzen 5 2600 | 6 / 12 | 3.4 GHz | 3.9 GHz | DDR4-2966 | 16 + 4 (NVMe) | 16MB | 65W | $199 |
The Core i5-9600K drops into existing 300-series motherboards after a BIOS update. Most, if not all of them, should support Core i5-9600K and its power requirements quite easily, though you might want to steer away from the lowest-cost models if you plan on overclocking.
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