Overclocking Intel’s Core i7-7700K: Kaby Lake Hits The Desktop!

Intel's new Kaby Lake CPU delivers on the clock speeds the company promised, but the power consumption and thermal characteristics were disappointing based on a leaked sample of the new chip we received and tested weeks ahead of its official launch.

The greatest gift a review editor can receive is unexpected hardware, especially when that hardware is an anticipated CPU. What would you do with an early sample of Intel’s next-gen Desktop CPU? Overclock, of course! So would I.

[Editor's Note: Intel declined to comment on our general findings. Although the CPU we received is not marked as an engineering part, we cannot confirm with certainty that it is a retail sample.]

I downloaded the latest Kaby Lake firmware for my most recently-tested Z170 motherboard sample and began running benchmarks.

That’s right, I said Z170. It turns out that while the next generation of motherboard may provide minor feature enhancements compared to the current generation, they’re both compatible with the new CPUs. That’s certain to be a big relief to overclockers who recently burned their Skylake-based processors, and it makes sense because of Intel’s recently-adjusted Tick-Tock-Tock strategy of releasing a new die process (Broadwell), followed by a new architecture (Skylake), followed by a process refinement or optimization (rather than another new process). To the point: Kaby Lake is a revision of Skylake.

Intel says that taller transistor fins and wider gate pitch endow its 14nm+ process with an additional 300 to 400 MHz clock rate capability. That’s huge if it turns out to be true. As a motherboard reviewer, it’s also one of the first things I wanted to test!

Kaby Lake

ModelCores/ThreadsCacheBaseline FrequencyMax Turbo BoostTDPIGP

Core i7-7700K

4/8

8MB

4.20 GHz

4.50 GHz

95W

630

Core i5-7600K

4/4

6MB

3.80 GHz

4.00 GHz

95W

630

Core i7-7700

4/8

8MB

3.60 GHz

4.20 GHz*

65W

630*

Core i5-7600

4/4

6MB

3.50 GHz

4.00 GHz*

65W

630*

Core i5-7500

4/4

6MB

3.40 GHz

3.80 GHz*

65W

630*

Skylake

Core i7-6700K

4/8

8MB

4.00 GHz

4.20 GHz

91W

530

Core i5-6600K

4/4

6MB

3.50 GHz

3.90 GHz

91W

530

Core i7-6700

4/8

8MB

3.40 GHz

4.00 GHz

65W

530

Core i5-6600

4/4

6MB

3.30 GHz

3.90 GHz

65W

530

Core i5-6500

4/4

6MB

3.20 GHz

3.60 GHz

65W

530

Intel accidentally leaked a little information about its desktop Kaby Lake CPUs in a document concerning other variations of the processor. What the company didn’t mention was the graphics version or Intel Turbo Boost frequencies. It’s because we’ve seen the Core i7-7700K and Core i5-7600K in action that we can provide that data for those two processors, and the asterisks in the chart indicate guesses derived from Intel’s previous models. We can’t say much about the revised Intel HD Graphics 630 without access to Intel documentation, which should be forthcoming when the company provides its usual information exchange closer to launch time; and none of our programs can pick out any pertinent information.

We’re also told that process improvements will enhance efficiency, but there is no free lunch. Intel didn’t change the core micro architecture between Skylake and Kaby Lake, and our motherboard didn’t even read a voltage reduction for the Core i7-7700K, compared to the Core i7-6700K. Our motherboard set the Core i7-7700K to 1.30V at its 4.50 GHz max turbo, whereupon it behaved exactly the way we’d expect our Core i7-6700K to act when overclocked to 4.50 GHz at 1.30V.

This particular motherboard dropped the full-load CPU voltage by around 20mV and the maximum full-load multiplier to 42x after I changed from firmware defaults to manual configuration and then back to automatic settings. It did this twice, both times after I initially used the CLR_CMOS jumper. Maximum power draw then dropped to 141W when turbo boost was disabled (bringing us down to the default 4.20 GHz; see chart below). Idle energy also dropped to 24W after several hours, but an idle period of that length exceeds normal test procedure.

The “no free lunch” statement still applies since 141W is more than 133W, but the only way I’ll reach an accurate conclusion about how much more power the higher 4.50 GHz frequency requires is to compare more boards. Update: Our first follow-up test has already confirmed a lower, 25W full-load power delta between the Core i7-7700K and Core i7-6700K when using a different motherboard. The new generation of motherboards that launch with this CPU will be the best boards to use for those tests, and we’ll have a batch of them ready when the NDAs of those manufacturers expire.

The power charts reveal my spoilers. This Core i7-7700K sample can be overclocked on this motherboard to 4.80 GHz at 1.30V, compared to the Core i7-6700K’s 4.60 GHz. I used Gigabyte’s GA-Z170X-Ultra for this test because it was my most recent review sample. The leftover chart tidbit — that I set the memory to DDR4-2933 — is due to this particular motherboard’s difficulty in achieving DDR4-3200 with four of my G.Skill DDR4-3600 modules installed.

The actual core overclock results of 4.78 GHz and 4.59 GHz are caused by the Z170X-Ultra’s oddball 99.65 MHz BCLK; the DRAM overclocks are identical due to motherboard limits; and I eventually gave up in frustration when trying to adjust the CPU BCLK with the new CPU. I’m sure a few of you Gigabyte fanatics have experienced the same BCLK stickiness.

The limits of the test board should leave plenty of excitement for future reviews, where new boards and memory may reveal new DRAM and BCLK overclocking heights! For now, I’m simply satisfied to find a solid core clock increase.

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161 comments
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    Top Comments
  • sarinaide
    The results are kind of disappointing for a 200mhz clock bump and 200mhz overclock head room you get twice the heat and power used, and 10% at best gains but more or less less than 5%. Sorry but maybe I missed something but that is not very good.
    17
  • weilin
    Tick -> Tock -> Tock should really just be Tick -> Tock -> Tweak
    13
  • ComputerSecurityGuy
    Does it really deserve the exclamation point?

    Kaby Lake has the expected identical IPC to Skylake but slightly higher clocks. The thermal figures are surprising, I would have thought that they wouldn't have done that bad.

    Anyone with Skylake shouldn't bother upgrading. As expected, Intel has produced a filler chip simply because their 10nm fab is taking longer than expected.
    12
  • Other Comments
  • sarinaide
    The results are kind of disappointing for a 200mhz clock bump and 200mhz overclock head room you get twice the heat and power used, and 10% at best gains but more or less less than 5%. Sorry but maybe I missed something but that is not very good.
    17
  • envy14tpe
    I'm salivating and excited to get this. Yeah...2017 upgrade time!
    -7
  • Daniel Ladishew
    Why would you use a motherboard with known issues (BLCK and RAM timings) to test a brand new CPU? It seems like you would have been better served taking the extra time to switch out to a motherboard that actually performs as expected with all previous hardware, so your baseline isn't questionable. If I were Intel, I wouldn't respond to these results either. Please test again with a better performing motherboard.
    8
  • ComputerSecurityGuy
    Does it really deserve the exclamation point?

    Kaby Lake has the expected identical IPC to Skylake but slightly higher clocks. The thermal figures are surprising, I would have thought that they wouldn't have done that bad.

    Anyone with Skylake shouldn't bother upgrading. As expected, Intel has produced a filler chip simply because their 10nm fab is taking longer than expected.
    12
  • elbert
    Looks like the 14nm+ is real given +200mhz overclock gain. Now just wonder what the leaked i3-7350K can get in overclock.
    -1
  • MusenMouse
    Maybe Intel's letting AMD get a free punch before they roll them next round :). Anyways maybe Kaby Lake will be like the Broadwell lineup, fleeting and in small numbers.
    3
  • logainofhades
    Anonymous said:
    Does it really deserve the exclamation point?

    Kaby Lake has the expected identical IPC to Skylake but slightly higher clocks. The thermal figures are surprising, I would have thought that they wouldn't have done that bad.

    Anyone with Skylake shouldn't bother upgrading. As expected, Intel has produced a filler chip simply because their 10nm fab is taking longer than expected.


    Depends on what skylake they have. An i3 6100 user may be interested in an i5 7500 or an i7 7700.
    5
  • ubercake
    At max graphic settings, gaming performance differences are negligible.

    I'd like to see the 7700K versus a Sandy Bridge with gaming. It's probably not a whole lot different since the year 2011.

    Hopefully AMD's Zen lives up to the hype "bulldozer" never did because Intel has no competition right now.
    12
  • Jamie_Lannister
    Im going to wait for cannonlake. For now I'll stick with my good old Ivy Bridge i5 3570k.
    2
  • Aristeid3s
    @ubercake, There are quite a few pieces of content out there showing a skylake i5 vs a 2500k. I don't remember specifics, but it was a pretty handy increase.
    0
  • InvalidError
    Anonymous said:
    The thermal figures are surprising, I would have thought that they wouldn't have done that bad.

    If you overclock Skylake to the same frequency as Kaby, Skylake catches up pretty quickly. They appear to be about the same on performance per watt. Nothing disappointing there, just unexceptional. I suppose that can be disappointing in its own way - another cycle of negligible performance and power efficiency gain.
    8
  • Malik 722
    so in oder to give kaby-lake full race i am gonna have to wait for november and december,because this is the time when ambient room temperature is lower on the equator side.
    2
  • why_wolf
    pretty much what I expected it to be like.
    0
  • weilin
    Tick -> Tock -> Tock should really just be Tick -> Tock -> Tweak
    13
  • joex444
    Is killing Skylake chips by overclocking really such an epidemic that the author needs to suggest twice that the intended reader of this article is one who has killed their 6700K?
    3
  • Rookie_MIB
    Anonymous said:
    At max graphic settings, gaming performance differences are negligible.

    I'd like to see the 7700K versus a Sandy Bridge with gaming. It's probably not a whole lot different since the year 2011.

    Hopefully AMD's Zen lives up to the hype "bulldozer" never did because Intel has no competition right now.


    I recently saw a review of Sandy Bridge vs Skylake - on average - there is a fairly decent improvement in FPS when running games at 1080p, indicating that there is a CPU constraint in there. However, the Sandy Bridge setup was quite playable (45+ fps on modern titles at ultra/high). Switch to 1440/4k and the difference drops indicating the GPU constraint. At 1440p the difference was minimal (10%) and 4k they were neck and neck.

    And you're right, AMD has a nice chance to get some licks in on Intel with Zen. Lets hope they pull it off and give them a run.
    4
  • ammaross
    Anonymous said:
    Looks like the 14nm+ is real given +200mhz overclock gain. Now just wonder what the leaked i3-7350K can get in overclock.


    Well, the i3 starts at 4.0Ghz, so I'd think it could hit 4.6 to 4.8 depending on board and sample. The i7-7700K can OC to 5.0Ghz on decent boards (not the crap one used in this review).
    0
  • Crashman
    Anonymous said:
    Anonymous said:
    Looks like the 14nm+ is real given +200mhz overclock gain. Now just wonder what the leaked i3-7350K can get in overclock.


    Well, the i3 starts at 4.0Ghz, so I'd think it could hit 4.6 to 4.8 depending on board and sample. The i7-7700K can OC to 5.0Ghz on decent boards (not the crap one used in this review).
    Take those with a grain of salt because the same thing was "shown" of Skylake, and what the screenshots actually did show on both cores was a core voltage that's impossible to cool cheaply at full clocks and eight threads of AVX-optimized Prime95.
    2
  • cordes85
    It adds nothing new, and frankly CPU power has hit the brick wall, we need AMD Zen to be a success, not because i want to buy them, but id like Intel to be cheaper. When will 6 cores be the norm for mainstream desktop Intel processors? Id like to see the next 8700k to be 6 cores@ 4Ghz-4.4 TB. I have a skylake i5 6500 bclk to 4.5GHZ, and an old Ivybridge I7 laptop which just goes on forever. I think only Ram, and GPU matters to a degree and obviously the switch from HDD to SSD. You'd think that M.2 would drive down prices of Sata SSD, but when will 1TB SSD be under £100?
    4
  • jasonf2
    If rumors are to be believed KabiLake's biggest advantages will be in the new chip-set. I think it is a forgone conclusion that KabiLake is Skylake+ (no one has called it anything different). But all we are seeing here are synthetic benchmarks that for all given purposes will only reflect clock (and power consumption when overclocked). Kabilake is not a new process node or design but a refinement with some extra hardware extensions and on board highly efficient encode\decode systems which will not reflect here but be really nice in real world application. I am also hoping for a little bit of optane love here too (if Wikipedia is to be believed).
    0