Intel Core i5-8600K Review: Coffee Lake's Jolting Value

For years, Intel dominated the high-end CPU market. As a result, enthusiasts had to pay a premium for its best processors. But AMD's four-, six-, and eight-core Ryzen models forced Intel to reconsider its value story. Our recent Core i7-8700K review showed that the company is serious about defending its turf. The six-core Coffee Lake-based flagship maintained the architecture's strength in lightly-threaded tasks, while extra Hyper-Threaded cores improved its performance in the heavy workloads AMD is doing so well in.

A $390 price tag is painfully expensive for most power users, though. That's why Tom's Hardware historically recommended Intel's unlocked Core i5 models to gamers. So how does the new Core i5-8600K fare against Core i7-8700K and, perhaps more important, AMD's Ryzen 7 and 5 CPUs?

Intel Core i5-8600K

Like the Core i7-8700K, Core i5-8600K sports six physical cores based on Intel's Skylake architecture. Hyper-Threading is disabled, similar to previous-generation Core i5 models. However, we still expect significant speed-ups across our benchmark suite thanks to higher clock rates and core count. Core i5-8600K features a similar graphics engine as its predecessor (never mind the UHD Graphics 630 branding), though it does benefit from a 50 MHz boost to 1150 MHz.

At the heart of Coffee Lake is Intel's 14nm++ manufacturing process. Delaying 10nm transistors forced the company to further refine its 14nm node. Attractive power optimizations, such as 52%-lower leakage than the original 14nm process, play a key role in enabling higher core counts within the same TDP envelope. Improved manufacturing yields higher performance as well; despite Core i5-8600K's more complex die, its 4.3 GHz peak Turbo Boost frequency is still higher than Core i5-7600K's 4.2 GHz ceiling.


14nm Broadwell (2014)
14nm Skylake (2015)
14nm+ Kaby Lake (2017)
14nm++ Coffee Lake (2017)
Maximum Turbo Frequency (GHz - Core i7 family)
3.8
4.3
4.5
4.7
Estimated Maximum Overclock Frequency (GHz - Conventional Cooling)
4.1
4.6
5.0
5.2

Of course, incrementally-higher peak clock rates are great. But adding 50% more cores promises to have a much more significant impact on the threaded benchmarks in our suite. Those workloads are the ones that AMD currently dominates. Intel did have to sacrifice base frequency in order to wedge six cores into a 95W TDP, though. Whereas the -7600K guaranteed 3.8 GHz across four cores, Core i5-8600K's base rate is 3.6 GHz. Consider this, though. With Turbo Boost enabled and four cores active, the -7600K hits 4 GHz. Core i5-8600K can take four cores up to 4.2 GHz, while its six-core bin maxes out at 4.1 GHz.

Active Cores
1
2
4
6
Intel Core i5-8600K
4.3 GHz
4.2 GHz
4.2 GHz
4.1 GHz
Intel Core i5-7600K
4.2 GHz
4.1 GHz
4.0 GHz
-

We also get a few extra cache slices as a byproduct of the additional cores, so the -8600K features 9MB of L3, compared to -7600K's 6MB. Memory improvements play a role in Coffee Lake's higher performance, too. The -8600K supports up to DDR4-2666, moving up to 42.7 GB/s across two 64-bit channels, versus DDR4-2400's 38.4 GB/s.

As we discussed in Core i7-8700K Review: Coffee Lake Brews A Great Gaming CPU, Intel improved the trace layout on Z370 motherboards to support the increased memory transfer rate. It also revised the power alignment inside the LGA 1151 interface to better accommodate the new six-core CPUs. This means you can't drop Coffee Lake-based processors into Z270 or Z170 motherboards. The requirement is a technical one, though that obviously doesn't make enthusiasts who recently purchased Z270 platforms feel any better.

Core i5-8600K's unlocked multiplier fits well with the Z-series boards, which are needed in order to manipulate its ratio. Intel also added a few new overclocking knobs and dials, such as per-core overclocking support, live memory timing adjustments, and memory multipliers up to 8400 MT/s. Like all of Intel's K-series processors, you're on the hook for a thermal solution; Core i5-8600K doesn't come with an air- or closed-loop liquid cooler.

Beyond the price of a heat sink or all-in-one, you're also looking at a steep premium over Core i5-7600K. Street pricing on the -8600K is currently $280, while the -7600K sells for $240. AMD's Ryzen 5 1600X is also available at $240, and the recently price-reduced Ryzen 7 1700 sits right around $300. Going the Ryzen route gives you the option of a lower-cost B350-based motherboard. And as if AMD's story needed strengthening, a bundled Wraith Spire cooler all but guarantees you could have an 8C/16T platform for less money than Intel's 6C/6T alternative. As always, we'll have to rely on the benchmarks to guide our recommendations.

MORE: Best CPUs

MORE: Intel & AMD Processor Hierarchy

MORE: All CPUs Content

Create a new thread in the Reviews comments forum about this subject
This thread is closed for comments
58 comments
Comment from the forums
    Your comment
  • logainofhades
    Great CPU, but the overall platform cost is a bit of a turn off, for me. I'd rather get a 1600, and a B350 board, to allow for a better GPU, if buying new. As stated in the review, even a 1700, with a less expensive board, is a very compelling option.
  • AS118
    Seems like a good product, but I'd like to see what the 8600 and 8500 non-k offers, and perhaps next year with the B360 boards that give them a more budget "locked cpu" option.

    I also feel that the availability will be low for Coffee Lake until the end of this year, particularly throughout the holiday season. Due to that concern (as well as the total cost of platform ownership) I think that Ryzen with its 1600 and 1700 CPU's along with the 1600x will be the value kings this year, with Coffee Lake not hitting it's stride until early next year.

    The fact that AMD's stuff doesn't have the same availability issues makes it a strong contender, imho, although Black Friday and Christmas sales will also like make Kaby Lake (and even Sky Lake) stuff at clearance prices appealing too, despite the lack of cores you'll find in Ryzen and now Coffee Lake.
  • almostdecent
    Since the chart shows the i5-8600k and the i5-8600K@4.9GHz at the same $260, I presume that means you achieved the overclock with the stock cooler.
  • ammaross
    It's kind of disappointing to see so many benchmarks where an i5 does as well or better than it's i7 counterpart. It just shows how poorly threaded some of these applications really are and almost necessitates running two benchmarks simultaneously to really judge the merit of these multi-core CPUs. Maybe run the photoshop test while rendering with After Effects or run a game benchmark while doing CPU h.265 handbrake.
  • almostdecent
    It is worth mentioning that this is essentially a paper launch at the moment, since none of the Coffee Lake processors are available anywhere.

    http://www.nowinstock.net/computers/processors/intel/

    and the rare place that has any, such as Microcenter, have gouging prices. Such as selling the plain i7-8700 (not the K version) with an MSRP of $300 for sale for $429.

    http://www.microcenter.com/product/486087/Core_i7-8700_Coffee_Lake_32_GHz_LGA_1151_Boxed_Processor
  • InvalidError
    Anonymous said:
    I also feel that the availability will be low for Coffee Lake until the end of this year, particularly throughout the holiday season.

    On September 20, Intel responded to a story about yet another 10nm schedule slip by saying that Cannon Lake will begin shipping in limited quantities to some laptop manufacturers with production ramping up in 1H2018. Limited Coffee Lake volume could be due to Intel deciding to upgrade production lines to 10nm for Cannon Lake instead of 14++.
  • TJ Hooker
    Anonymous said:
    Since the chart shows the i5-8600k and the i5-8600K@4.9GHz at the same $260, I presume that means you achieved the overclock with the stock cooler.

    Not sure if you were being sarcastic, but the 8600K doesn't have a stock cooler.

    There are two different sets of graphs, one that looks at CPU only costs and the other that considers CPU, mobo, and cooler costs. In the latter, the 8600K at 4.9GHz is clearly shown to cost more.
  • InvalidError
    Anonymous said:
    Since the chart shows the i5-8600k and the i5-8600K@4.9GHz at the same $260, I presume that means you achieved the overclock with the stock cooler.

    Intel hasn't included a stock HSF with their unlocked CPUs since Skylake so on top of paying more for the unlock, you also get shafted by the price of a stock cooler which you no longer get on top of it. You need an aftermarket cooler for both stock and OC.

    Same thing with AMD's Ryzen nnnnX CPUs.
  • YoAndy
    Anonymous said:
    Great CPU, but the overall platform cost is a bit of a turn off, for me. I'd rather get a 1600, and a B350 board, to allow for a better GPU, if buying new. As stated in the review, even a 1700, with a less expensive board, is a very compelling option.



    A better GPU?//Why would you do that. at 1080p Ryzen will (bottleneck) hold back powerful GPU's, It won't give you equal performance. I bought a Ryzen for pure gaming and i ended up selling it..
  • acosta.87
    Anonymous said:
    Great CPU, but the overall platform cost is a bit of a turn off, for me. I'd rather get a 1600, and a B350 board, to allow for a better GPU, if buying new. As stated in the review, even a 1700, with a less expensive board, is a very compelling option.



    B350 VRM's are pretty low quality for any sort of OC unless it's a mild one so for me that's a no go. If you're primarily into gaming then the 1600 has nothing on the i5, it simply trails it whether at stock settings or OC'd and even at productivity it beats a 1600 Ryzen processors in most task even with a 6 thread deficit so it's a pretty good investment overall.
  • YoAndy
    Anonymous said:
    Since the chart shows the i5-8600k and the i5-8600K@4.9GHz at the same $260, I presume that means you achieved the overclock with the stock cooler.


    They don't come with a cooler!!!!!:lol:,, Intel sells their unlocked processors without heatsinks because overclockers will pretty much use liquid set ups or buy their own.
  • Wisecracker
    Anonymous said:
    Great CPU, but the overall platform cost is a bit of a turn off, for me. I'd rather get a 1600, and a B350 board, to allow for a better GPU, if buying new. As stated in the review, even a 1700, with a less expensive board, is a very compelling option.



    Pretty much this. AMD has nailed the price/performance sweet-spot with the Ryzen 5 1600/X hex cores --- especially with the combo deals out there.

    Not quite enough to move me off my FX-6350, though :lol: maybe if THG would work one into the charts at 4.7GHz or so for comparison (hint hint)

    With the extra costs involved it's too tough to beat the Ryzen 5s and the Kaby/Sandy i5s just to be "King of The Hill for A Day" ...
  • Yuka
    This might need a fix:
    Quote:
    Base Frequency
    1 core: 3.6 GHz, 2 cores: 4.2 GHz: four cores: 4.2 GHz, 6 cores: 4.1 GHz


    Overall, no surprises. Great gaming CPU, but not necessarily the best value. Thank God we now have more options.

    Cheers!

    EDIT: Typo.
  • elbert
    Looks like the i5-8600k is the best option for gamings till you hit the tippy top.
  • DrakeFS
    So does remain the best price/performance for gaming after factoring in the cost of motherboards?
  • AgentLozen
    These 1080p 240Hz gaming monitors have been popping up recently. The gaming benchmarks at 1080p show that none of them can reach 200+ fps on modern hardware. Even overclocked to 4.9GHz, you'll have to reduce the settings if you want to see the full glory of your new 240Hz monitor. Or play Half Life 2.
  • logainofhades
    Anonymous said:
    Anonymous said:
    Great CPU, but the overall platform cost is a bit of a turn off, for me. I'd rather get a 1600, and a B350 board, to allow for a better GPU, if buying new. As stated in the review, even a 1700, with a less expensive board, is a very compelling option.



    A better GPU?//Why would you do that. at 1080p Ryzen will (bottleneck) hold back powerful GPU's, It won't give you equal performance. I bought a Ryzen for pure gaming and i ended up selling it..


    PCPartPicker part list / Price breakdown by merchant

    CPU: Intel - Core i5-8600K 3.6GHz 6-Core Processor ($279.89 @ B&H)
    CPU Cooler: CRYORIG - H5 Universal 65.0 CFM CPU Cooler ($42.89 @ OutletPC)
    Motherboard: ASRock - Z370 Pro4 ATX LGA1151 Motherboard ($121.98 @ Newegg)
    Total: $444.76
    Prices include shipping, taxes, and discounts when available
    Generated by PCPartPicker 2017-10-17 12:02 EDT-0400

    vs

    PCPartPicker part list / Price breakdown by merchant

    CPU: AMD - Ryzen 5 1600 3.2GHz 6-Core Processor ($193.89 @ OutletPC)
    Motherboard: ASRock - AB350 Pro4 ATX AM4 Motherboard ($87.39 @ OutletPC)
    Total: $281.28
    Prices include shipping, taxes, and discounts when available
    Generated by PCPartPicker 2017-10-17 12:02 EDT-0400

    That price difference is enough to get a GTX 1070, vs a GTX 1060 6gb. Unless a game is stupidly CPU bound, there is no way an i5 with a GTX 1060 6gb, is going to beat an r5 1600, with a GTX 1070. Also, I play @1440p, so the CPU gap is shorter anyway. ;)
  • TJ Hooker
    Anonymous said:
    Anonymous said:
    Great CPU, but the overall platform cost is a bit of a turn off, for me. I'd rather get a 1600, and a B350 board, to allow for a better GPU, if buying new. As stated in the review, even a 1700, with a less expensive board, is a very compelling option.

    B350 VRM's are pretty low quality for any sort of OC unless it's a mild one so for me that's a no go.

    1) Chipset does not dictate VRM design/quality
    2) There are plenty of people getting good overclocks with B350 boards. I mean, Ryzen isn't a great overclocker overall, but you're probably not going to be (significantly) limited by your mobo. Especially because Ryzen isn't particularly power hungry.
  • ammaross
    Anonymous said:
    Seems like a good product, but I'd like to see what the 8600 and 8500 non-k offers, and perhaps next year with the B360 boards that give them a more budget "locked cpu" option.


    The i5-8500/8600 are even worse off. They have a 2.8Ghz base clock and absolutely no promises to boost any higher. It's pure silicon lottery with those and remember, they didn't quality for the K-series, so no way are they going to boost as well as those.
  • TJ Hooker
    Anonymous said:
    Anonymous said:
    Seems like a good product, but I'd like to see what the 8600 and 8500 non-k offers, and perhaps next year with the B360 boards that give them a more budget "locked cpu" option.

    The i5-8500/8600 are even worse off. They have a 2.8Ghz base clock and absolutely no promises to boost any higher. It's pure silicon lottery with those and remember, they didn't quality for the K-series, so no way are they going to boost as well as those.

    Eh, AFAIK for at least the last several generations you could pretty much assume that an Intel CPU would maintain its max boost clock indefinitely under load, unless you had crap cooling or something. I don't know if there's any reason to think things will be any different for Coffee Lake.