Core i7-8700K Review: Coffee Lake Brews A Great Gaming CPU

Intel’s Core 2 Quad processors debuted with four cores in 2006. Although six-core models landed four years later in the high-end desktop space, the company’s most accessible chips topped out in quad-core configurations for more than a decade. The Coffee Lake era begins with Intel upending its mainstream line-up by adding two more cores to Core i7, i5, and i3 families. Call this a much-needed improvement, cleverly timed to stave off AMD's core-laden Ryzen assault.

Of course, while Intel's accelerated Coffee Lake-S launch makes it look today's unveiling is a direct response to heated competition, in reality, the long incubation period for new processors means it’s more likely the result of 10nm manufacturing delays.

Just last year, Intel announced a new process-architecture-optimize cadence designed to deliver smaller transistors every third generation. That's a profound departure from the glory days of Intel’s tick-tock model. The latest 14nm++ process is the fourth outing of the 14nm node, which originally debuted with Broadwell back in 2014. So, it appears that PAO is already falling by the wayside. In the days of tick-tock, we'd also be talking about a new architecture right now. But Coffee Lake employs the same Skylake design as Kaby Lake before it. We also get the same fundamental integrated graphics engine found in the previous generation. To be sure, Coffee Lake is another iterative update.

But there’s nothing mundane about adding more cores. Intel claims Coffee Lake offers up to 25% more gaming performance and up to 45% more “mega-tasking” performance. Given similar price points versus Kaby Lake, we're almost certainly looking at a huge step forward in value.

This is obviously a busy year for Intel. But as if the company's product stack wasn't already confusing, its eighth-generation portfolio draws from three separate architectures, including 14nm+ Kaby Lake-R (refresh), 14nm++ Coffee Lake, and 10nm Cannon Lake, which should land next year.

Intel Core i7-8700K

Core i7-8700K serves as this generation's flagship, sporting six Hyper-Threaded cores. Already, that's a big increase from Kaby Lake's 4C/8T maximum. It features the company's highest clock rates, accelerating up to 4.7 GHz via Turbo Boost. The -8700K does sacrifice some base frequency in exchange for a higher core count, though. Its 3.7 GHz specification is 500 MHz lower than the -7700K, offsetting the increased power consumption and heat generated by a 6C/12T configuration.

The -8700K's Coffee Lake design utilizes a 14nm++ process, which Intel claims offers 26% more performance and 52% less leakage power than first-generation 14nm manufacturing. Those advances enable the higher Turbo Boost bins and reduce consumption enough to carve out room for extra cores. A more complex die does necessitate a TDP rating of up to 95W. But that's only 4% higher than Core i7-7700K. And as we've seen before, Turbo Boost allows the CPU to operate beyond its rated TDP as long as current, power, and temperature fall below specified limits. As you might imagine, then, the impact of two additional cores is felt under load.

The top 4.7 GHz Turbo Boost bin should help improve performance in lightly-threaded applications. But Core i7-8700K also includes aggressive multi-core bins to help chew through threaded workloads. Because these CPUs employ Intel's Skylake architecture, we aren't expecting any speed-ups attributable to IPC throughput. All gains come from core count and clock rate alone. Intel isn't officially disclosing a die size or transistor count, but early delidding efforts indicate a ~151mm2 area. That's naturally larger than Kaby Lake's ~122mm2, reflecting the additional execution and cache resources. Intel confirms that Coffee Lake continues to employ its ring bus, rather than Skylake-X's mesh topology.

Active Cores
1
2
4
6
Intel Core i7-8700K
4.7 GHz
4.6 GHz
4.4 GHz
4.3 GHz
Intel Core i7-7700K
4.5 GHz
4.4 GHz
4.4 GHz
-

Intel also adds 50% more cores to its Core i5 family, and doubles Core i3's core count. But it pulls Hyper-Threading support from Core i3 in the process. Nevertheless, we expect gamers to realize palpable gains moving from dual-core Hyper-Threaded platforms to inexpensive quad-core setups.

Core i5 and i7 also support speedier DDR4-2666 transfer rates, up from Kaby Lake's DDR4-2400 spec. Core i3 remains limited to DDR4-2400, though. This could just be Intel's attempt to segment its line-up, or perhaps the Core i3s are really just quad-core Kaby Lake designs transplanted onto a 14nm++ process. 


Intel Core
i7-8700K
Intel Core
i7-8700
Intel Core i5-8600K
Intel Core i5-8400
Intel Core i3-8350K
Intel Core i3-8100
Socket
LGA 1151
LGA 1151
LGA 1151LGA 1151LGA 1151LGA 1151
Cores/Threads
6 / 12
6 / 12
6 / 6
6 / 6
 4 / 4
4 / 4
Base Frequency
3.7 GHz
3.2 GHz
3.6 GHz
2.8 GHz
4.0 GHz
3.6 GHz
Boost Frequency
4.7 GHz
4.6 GHz
4.3 GHz
4.0 GHz
N/A
N/A
Memory Speed
DDR4-2666
DDR4-2666
DDR4-2666DDR4-2666DDR4-2400
DDR4-2400
Memory Controller
Dual-Channel
Dual-Channel
Dual-ChannelDual-ChannelDual-Channel
Dual-Channel
Unlocked Multiplier
Yes
No
YesNoYes
No
PCIe Lanes
x16 Gen3
x16 Gen3
x16 Gen3x16 Gen3x16 Gen3
x16 Gen3
Integrated Graphics
Intel UHD Graphics 630 (up to 1200 MHz)
Intel UHD Graphics 630 (up to 1200 MHz)Intel UHD Graphics 630 (up to 1150 MHz)Intel UHD Graphics 630 (up to 1150 MHz)Intel UHD Graphics 630 (up to 1150 MHz)Intel UHD Graphics 630 (up to 1150 MHz)
Cache (L2+L3)
13.5MB13.5MB
10.5MB10.5MB9MB
7MB
Architecture
Coffee Lake
Coffee LakeCoffee LakeCoffee LakeCoffee Lake
Coffee Lake
Process
14nm++
14nm++14nm++14nm++14nm++14nm++
TDP
95W
65W
95W
65W
91W
65W
Price
(per 1K Unit)
$359
$303
$257
$182
$168
$117

Unfortunately, Intel still doesn't enable Turbo Boost on its Core i3 CPUs. So, we could see a performance dip in lightly threaded workloads due to Coffee Lake's lower base frequencies. You do get 100% more cores in exchange, though. Physical cores are always preferable to logical ones, so the new implementation of Core i3 should come out ahead in most of our benchmarks.

As expected, most models continue to wield 2MB of L3 and 256KB of L2 cache per core. As a side effect of its higher core counts, then, Coffee Lake processors enjoy the benefits of more cache. Core i3-8100 is the lone exception with only 6MB of L3 cache.

PCIe connectivity remains unchanged; you get 16 lanes of third-gen PCIe from the CPU's controller. Intel reminds us, though, that it offers up to 40 lanes when we add the platform controller hub's 24.

You'll need a Z370-based motherboard for Coffee Lake processors. The 200-series chipsets are not compatible. And in a clear indication that Intel really hurried its launch schedule, less expensive B- or H-series chipsets won't be ready until next year. Paying a premium for Z-class core logic isn't much of a surprise for enthusiasts, who need the higher-end chipset to support unlocked multipliers. But it's a little bit overkill for everyone else.

Coffee Lake
Intel Core
i7-8700K
Intel Core
i7-8700
Intel Core i5-8600KIntel Core i5-8400Intel Core i3-8350KIntel Core i3-8100
Cost Per Core/Thread$59.83 / $29.92
$50.50 / $25.25
$42.83 / $42.83
$30.33 / $30.33
$42 / $42
$29.95 / $29.95
Kaby Lake
Intel Core i7-7700KIntel Core i7-7700Intel Core i5-7600KIntel Core i5-7400Intel i3-7350KIntel i3-7100
Cost Per Core/Thread$84.75 / $42.38
$75.75 / $37.88
$60.50 / $60.50
$45.50 / $45.50
$84 / $42
$58.50 / $29.95
RyzenRyzen 7
1700X
Ryzen 7
1700
Ryzen 5
1600X
Ryzen 5
1500X
Ryzen 5
1400
Ryzen 3
1300X
Cost Per Core/Thread$49.88 / $24.94
$41.13 / $20.56
$41.50 / $20.75
$47.50 / $23.75
$42.25 / $21.12
$32.50 / $32.50

We're using Intel's 1K unit pricing for comparisons to the Kaby Lake models and AMD's MSRP for price-equivalent Ryzen chips. We may see higher prices on Intel's CPUs at retail, while AMD models routinely sell below MSRP.

Intel adds a ~$20 premium to its K-series SKUs compared to their Kaby Lake equivalents. Overall, though, you pay less per core. Again, Intel removed Hyper-Threading from its Core i3s, so their price per thread remains unchanged. With the exception of Ryzen 3, AMD maintains a price advantage across its portfolio, due in part to SMT on the Ryzen 5 family. The benchmarks will give us a better idea of performance-per-dollar compared to Kaby Lake and Ryzen, though.    

Overclocking headroom was one of Kaby Lake's biggest advantages due to Ryzen's limited scaling. Intel adds per-core overclocking support to this generation, but doesn't provide per-core voltage and P-state controls. It also enables live memory timing adjustments (without rebooting), along with memory multipliers up to 8400 MT/s, so you don't have to adjust the BCLK frequency to chase bleeding-edge transfer rates. Finally, enhanced GT and Ring PLL Trim controls add more granular control.

Intel makes some power optimizations to its interface that promise to extend the advantage while overclocking. However, the company continues to insist on using thermal paste between its die and IHS, rather than solder. Like all unlocked Intel models, the Core i7-8700K doesn't include a stock cooler.

Nevertheless, we have to give the big company credit for staying on its toes this year. It already introduced Kaby Lake, Skylake-X, and Kaby Lake-Refresh. Next year, we'll have new Pentium and Celeron line-ups headed our way. But for now, we're looking forward to testing what Intel claims is its best gaming chip yet.

MORE: Best CPUs

MORE: Intel & AMD Processor Hierarchy

MORE: All CPUs Content

Create a new thread in the Reviews comments forum about this subject
162 comments
Comment from the forums
    Your comment
    Top Comments
  • FormatC
    Anonymous said:
    Nearly 90 degrees Celsius when overclocked gaming on an AiO. Prettttttty toasty!

    The reason is simple:
    The built-in frying fat between IHS and die :)
    15
  • FormatC
    @LilDog1291:
    A delidded i7-8700K is around 15-20 degrees cooler. The problem isn't the architecture, but the TIM instead of solder.
    12
  • ingtar33
    this article is filled with subtle comments about all the extra stuff they needed to do to keep this thing from melting through the floor.

    If you had to take all these extra steps on an AMD cpu you'd have written an expose on how hot the chip is. But you just brush it off like its nothing in this article.

    BTW: if you can't run prime95 for half a day stable on an overclock, it's not a real overclock. It's just a silly benching number. Check my sig. Thats a silly benching number. Could I get a fx8320 to run at 5.3ghz? sure, windows booted and i validated it. But could I DO anything with that clock speed? nope. I've seen a number of review sites today post 5.0-5.1 ghz overclock numbers for coffee lake, yet not a single one of them could run a serious prime run on those numbers. Heck, can you even run prime at stock on this chip? I'd like to know that before I consider this chip for purchase to replace my i5.
    12
  • Other Comments
  • cknobman
    Looks like it might be time for AMD to lower prices.

    AMD really has shaken Intel up, never would I have dreamed (before this year) I'd see Intels best gaming cpu (especially a K model) release at $360.
    5
  • AgentLozen
    AMD's price per core is still very strong. It struggles in gaming at 1080p but Tomshardware didn't provide data in 1440p or 4K.

    I'm not yet convinced that AMD is in trouble.
    9
  • saunupe1911
    Hmmm is it worth a skylake 6700K that's stable at 4.6 Overclock to upgrade? Probably not. I wouldn't mind 6 cores though. I wonder how many will hit 5.0!
    2
  • jroc188
    8700k is $480ca got the R5 1600 for $255ca and mobo for $120ca. $375 all together and more then happy with the gaming results. But the 8700k dose look sweet on the benchmarks. AMD with a price drop will still sell well
    7
  • shrapnel_indie
    Quote:
    Of course, while Intel's accelerated Coffee Lake-S launch makes it look today's unveiling is a direct response to heated competition, in reality, the long incubation period for new processors means it’s more likely the result of 10nm manufacturing delays.


    Ummm... Yeah, the design may have been kicking around, and ready to go before Ryzen, but when it is released months earlier than scheduled.... Saying that it wasn't a response to Ryzen seems more like misinformation more than pure fact. Yeah, I don't doubt 10nm manufacturing delays played a part in the previous release date, but Ryzen forced its release a little earlier than planned.
    10
  • Billy Gates
    Intel caught AMD with their pants down. Panic mode incoming!
    -14
  • bloodroses
    To AMD fanbois who claimed that Intel was toast and couldn't respond to Ryzen's release, here's Intel's Mic drop. *thud*

    For the rest of us consumers, this is great news for continued strong competition at reduced prices from both companies. :)
    -5
  • massacre.h4te
    Nearly 90 degrees Celsius when overclocked gaming on an AiO. Prettttttty toasty!
    4
  • saunupe1911
    Anonymous said:
    To AMD fanbois who claimed that Intel was toast and couldn't respond to Ryzen's release, here's Intel's Mic drop. *thud*

    For the rest of us consumers, this is great news for continued strong competition at reduced prices from both companies. :)


    Z370 motherboards are expensive though...sheesh. And you gotta reach out to liquid cooling companies for attachments for mounting to this socket. Canon Lake may be out before you can get everything situated for a nice 8700k upgrade lmao.
    2
  • FormatC
    Anonymous said:
    Nearly 90 degrees Celsius when overclocked gaming on an AiO. Prettttttty toasty!

    The reason is simple:
    The built-in frying fat between IHS and die :)
    15
  • LilDog1291
    Anonymous said:
    To AMD fanbois who claimed that Intel was toast and couldn't respond to Ryzen's release, here's Intel's Mic drop. *thud*

    For the rest of us consumers, this is great news for continued strong competition at reduced prices from both companies. :)


    I don't know if I would call 90C+ on a chiller cooler (granted its a high overclock but the 7700k had the same problem) a mic drop but it is definitely a step in the right direction. If they can get their temperatures under control in the next generation they will win my vote back.
    3
  • Billy Gates
    Intel caught AMD with their pants down. Price drop is imminent.
    -8
  • FormatC
    @LilDog1291:
    A delidded i7-8700K is around 15-20 degrees cooler. The problem isn't the architecture, but the TIM instead of solder.
    12
  • garba78
    Disappointed :(
    0
  • madmatt30
    @Billy Gatez - Its $360 , amd have no reason whatsoever to drop their prices at the moment.

    The ryzen 1600 is less than $200, Intel don't have an answer to that pricepoint .

    The only chips that should (& will) worry amd is the cheapest locked quad i3 , & the cheapest locked 6 core i5

    Nothing else is relevant to them price wise.
    4
  • JCFca1992
    I have a 6600K which I can't overclock past 4.2ghz without lots of heat (lost the Silicon Lottery).

    I play lots of 64 player BF1 and regularly see 100% CPU usage.

    Is this worth the upgrade long term?
    0
  • Aspiring techie
    I'm waiting to see what happens when AMD releases Ryzen on a better process. Maybe Intel's clock speed advantage will be shrunk.
    3
  • saunupe1911
    Anonymous said:
    @LilDog1291:
    A delidded i7-8700K is around 15-20 degrees cooler. The problem isn't the architecture, but the TIM instead of solder.


    90% of consumers aren't purchasing delidded processors. Only extreme enthusiasts.
    7
  • Aspiring techie
    I find it interesting that an 8-core, overclocked Ryzen 7 1800X is using less power than a stock i7 8700K.

    Also, it would be interesting to compare a Kaby Lake i7 vs a Coffee Lake i5 at the same clock rates. Does a 4 core 8 thread CPU beat a 6 core 6 thread CPU?
    6
  • dstarr3
    Well, AMD didn't wear that crown for very long. But thanks to them for shaking up the market!
    0