It’s the Intel review you’ve been waiting for. Today is the launch of the first two CPUs from Intel’s Skylake architecture, the 6th Generation Core i7-6700K and the Core i5-6600K. With the new processors we get a new architecture, a new socket, the move to DDR4 and the potential to increase both performance and efficiency at the same time. A lot of readers have asked the question – is it time to upgrade? We had a CPU or two in to test to answer that question.

Launch Day for Skylake-K: August 5th

For those in the industry, predicting Skylake’s launch has been a minefield. Even at Computex in June, some companies were discussing a large six-week window in which they expected Skylake but were waiting on official dates. But as we've seen with a number of previous Intel mainstream launches, Intel likes to aim at the gaming crowds release at a gaming events. It just so happens that today is Gamescom in Germany, two weeks before what everyone expected would be a launch at Intel’s Developer Forum in mid-August.

Image courtesy of Splave

Today is a full launch for the Skylake-K processors, with the two CPUs being launched alongside new Z170 series motherboards and dual channel DDR4 memory kits. Having spoken to a few retailers, they have stock ready to go today. That being said, a number of them would have liked more stock on launch day, suggesting that they expect the processors to sell out rather quickly when the buy buttons are activated.

All the motherboard manufacturers should be ready to go as well – take a look at our breakdown of the retail motherboard information we could get before launch for a good overview of what to expect this generation. DDR4 manufacturers have been selling the new standard of memory for over a year due to Intel’s high-end X99 platform supporting it, but today will see the introduction of dual channel kits to go with the Skylake platform as well as a number of higher speed modules ready and waiting.

‘Where are the non-K processors?!’ you may ask. Intel tells us that these will be released later in the year, sometime in Q3. As a result, we have to wait and see what range of models come out at that point and we will get a number in to review.

Retail Packaging

To go with the launch is a new look of Intel's Core processor packaging, in part to appeal to the gaming crowd. As the gaming industry is considered one of the few remaining areas for potentially large growth in the PC industry, Intel is increasing its focus on gaming as a result.

Aside from changing the graphics on the box, it has been reported – and seemingly confirmed by the thinner boxes in the official pictures from Intel – that these processors will not be shipped with a stock Intel cooler. Users will have to purchase third party coolers. Part of this makes sense – overclocking processors need beefier cooling in order to extract the maximum overclock and buying something above the stock cooler should be good. The downside of not having a stock cooler means an added cost to the end user. However as the hole mounting for the new socket, LGA1151, is similar to that of LGA1150/1155/1156 – spacing is still 75mm – many existing CPU coolers for the current LGA115x sockets should be compatible, making it possible to reuse many coolers for no more than the cost of a new thermal paste application.

For users looking for a new air or liquid cooler, head on over to our recent roundup of Top Tier CPU Air Coolers Q3 2015: 9-Way Roundup Review and the Closed Loop AIO Liquid Coolers: 14-way Mega Roundup Review published last year.

The Skylake CPUs: Intel’s 6th Generation Core

Intel’s tick-tock strategy has been the bedrock of their application to bring new processors to the market, growing in terms of user experience for either power, efficiency, or both. It has been noted that certain generations either have an enterprise focus or a mobile-first focus, which always seems to tip the scales in one direction of the other. However, with the recent announcement of a third CPU line at 14nm called Kaby Lake for 2016, tick-tock just became tick-tock-tock.

Intel's Tick-Tock Cadence
Microarchitecture Process Node Tick or Tock Release Year
Conroe/Merom 65nm Tock 2006
Penryn 45nm Tick 2007
Nehalem 45nm Tock 2008
Westmere 32nm Tick 2010
Sandy Bridge 32nm Tock 2011
Ivy Bridge 22nm Tick 2012
Haswell 22nm Tock 2013
Broadwell 14nm Tick 2014
Skylake 14nm Tock 2015
Kaby Lake (link)? 14nm Tock 2016 ?

Intel’s early issues with 14nm yields have been well documented and we won’t go into them here, but 14nm is a more expensive process with an increased number of lithography steps as we reach the limits of current semiconductor technology. FinFET was introduced back in 22nm, but to move down to 10nm makes either the current process more expensive or other methods have to be used. As a result, we see Moore’s Law stretching out from an 18-24 month cadence to a 24-30 month cadence for the first time in fifty years. As we’ve seen with the graphics card market recently stalling at 28nm, there is a need (or at least opportunity) to develop more power efficient architectures rather than just relying on die shrinks to do it for you.

Future development aside, today Skylake will hit the shelves in the form of two overclockable processors, the Core i7-6700K and the Core i5-6600K.

Intel i7 Lineup
  i7-4770K i7-5775C i7-6700K
Price $339 $366 $350
Cores 4 4 4
Threads 8 8 8
Base CPU Freq. 3.5 GHz 3.3 GHz 4.0 GHz
Turbo CPU Freq. 3.9 GHz 3.7 GHz 4.2 GHz
Graphics HD 4600 (GT2) Iris Pro 6200 (GT3e) HD 530 (GT2)
EUs 20 48 24
iGPU Freq. 1250MHz 1100MHz 1150MHz
TDP 84W 65W 91W
DDR3/L Freq. 1600MHz 1600MHz 1600MHz
DDR4 Freq. - - 2133MHz
L3 Cache 8MB 6MB 8MB
L4 Cache None 128MB (Crystal Well) None
Interface LGA1150 LGA1150 LGA1151

As with previous nomenclature, the i7 model will be quad core CPU with HyperThreading and 8MB of L3 cache. This matches up with the Haswell parts to which Skylake is more closely aligned (Desktop Broadwell is rather a blip, using an external on-package eDRAM and you can read our review here), in a large number of aspects including the other cache levels. The 6700K runs at a base frequency of 4.0 GHz and an all-core frequency of 4.2 GHz. This is a slight speed bump over the 4770K which was launched at the start of Haswell, but a minor reduction in clockspeeds compared to the i7-4790K, which was an upgraded Haswell part launched later under the name of ‘Devil’s Canyon’.

The integrated graphics nomenclature has changed, with the new i7-6700K having the Intel HD 530 graphics, compared to the HD4600 in the Haswell parts. We know that the HD 530, like the HD 4600, has 24 of Intel’s execution units in the iGPU, and they run at a peak frequency of 1150 MHz. The introduction of the HD 530 marks the launch of Intel’s 9th generation graphics, and we'll cover Gen9 in a bit more detail later.

Intel i5 Lineup
  i5-4670K i5-5675C i5-6600K
Price $242 $276 $243
Cores 4 4 4
Threads 4 4 4
Base CPU Freq. 3.4 GHz 3.1 GHz 3.5 GHz
Turbo CPU Freq. 3.8 GHz 3.6 GHz 3.9 GHz
Graphics HD 4600 (GT2) Iris Pro 6200 (GT3e) HD 530 (GT2)
EUs 20 48 24
iGPU Freq. 1200MHz 1100MHz 1150MHz ?
TDP 84W 65W 91W
DDR3/L Freq. 1600MHz 1600MHz 1600MHz
DDR4 Freq. - - 2133MHz
L3 Cache 6MB 4MB 6MB
L4 Cache None 128MB (Crystal Well) None
Interface LGA1150 LGA1150 LGA1151

The i5 model for Skylake also has quad cores, but without HyperThreading and only 6MB of L3 cache. Like the i7, it also has the Intel HD 530 graphics but operates at a lower frequency band.

Both the Skylake processors will support DDR4 and DDR3L memory in order to ease the transition to DDR4 for the mainstream segment, although it should be said that DDR3L is implemented here due to its lower than standard DDR3 operating voltage of 1.35 volts. This more closely aligns with DDR4’s standard voltage of 1.20 volts or the high end DDR4 kits at 1.35 volts, and as a result we are told that motherboards that support DDR3L will typically only be qualified to run DDR3L kits, rather than DDR3 kits.

This leads onto the point that both of the K processors for Skylake sit at 91W, which is a small increase over Haswell at 84W and Devil’s Canyon at 88W. In the past Intel has historically run a 1:1 policy whereby a 1% performance gain must come at a maximum of a 1% power penalty – this was adjust to 2:1 for Broadwell, and we should assume that Skylake had similar requirements during the planning stage. Depending on the specific architecture details, one potential source for this increase in power consumption may be the dual memory controller design, although Skylake has a significant number of features to differentiate itself from Haswell.

Also Launching Today: Z170 Motherboards, Dual Channel DDR4 Kits
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  • experttech - Monday, August 10, 2015 - link

    I have a Sandy Bridge 2600K running on a Asus H67 EVO motherboard, so not overclocked. My motherboard is slowly dying. First the obboard sound died, then the reset is now working. Now I am wondering whether to upgrade the motherboard to an overclockable Sandy Bridge motherboard or jump the wagon to 6700K. I mostly do Video Editing and Encoding, no gaming. or wait till the motherboard dies completely and hope SkyLake E or Kaby Lake is out by that time. Any suggestions?
  • sonny73n - Wednesday, August 12, 2015 - link

    2600K is an excellent chip. I'd rather have the i7-2600K than the new i5-6600K. You should get a new MB Z77 but there's not many still available now. I only saw 1 Z77 on Newegg, it's the Asrock and I think it costs around $160. You can also find used Z68 and Z77 MBs on Amazon or eBay but I wouldn't recommend it. Video editing with the 2600K is a piece of cake and x264 encoding is not bad either. Keep the chip and spend your money on a good video card and a nice 4K ips monitor.
  • experttech - Thursday, August 13, 2015 - link

    Thanks for your reply. I too realized the same, I did notice the only Z77 Asrock motherboard (which is an excellent motherboard by the way) but for the price, I can't justify buying it especially since so many options are available in the new platform. One interesting thing I noticed is that with the newer instruction sets, my laptop with i5 5200U actually renders some frames very fast but overall, my i7 2600K renders the finished movie quicker. So though there are IPC improvements in the newer chips, the basic features (performance, mutithreading etc) haven't changed night and day. Of course I am comparing a Sandy bridge i7 to a lower clocked Broadwell i5 but I am not sure if there will be a tangible difference upgrading to SkyLake as of now. So you are right my friend and thanks for the advice!

    I do have a 1440p monitor and its amazing how much real estate you get going from 1080p. Definitely one of the best upgrades I made. I will look into a 4K monitor as they have come down quite a bit in price.
  • phillipstuerzl - Monday, August 10, 2015 - link


    On your 5th page, under Test Setup, you list the i5 6600K as being 4C/8T. This is incorrect. It is not hyperthreaded, and only 4C/4T.

    Great article!
  • Ryan Smith - Tuesday, August 11, 2015 - link

  • DannyDan - Monday, August 10, 2015 - link

    So do we expect the 1151 socket to have a few good upgraded processors down the road? It really sucked getting a socket 1156 CPU.
  • mdw9604 - Tuesday, August 11, 2015 - link

    Moore's law is a crock of $%!24. 7 years later and Intel still hasn't doubled the performance the i7 870. Core for Core.

    The may be able to cram more transistors into a smaller space, but doesn't mean better performance.
  • Oxford Guy - Thursday, August 13, 2015 - link

    It's funny how every time it fails people say it is being "adjusted", "extended", "massaged", "modified", or something like that. Either it works or it doesn't. It should be called Moore's Heuristic = "process density increases over time" (duh).
  • ES_Revenge - Saturday, August 15, 2015 - link

    You misunderstand Moore's Law. Moore's law has nothing [necessarily] to do with performance. Moore's law only states that the number of transistors possible in a given space will double every two years. It also doesn't just apply to Intel and mainstream CPUs, it applies to *all* integrated circuits. Everything from CPUs to EEPROMS, to SOCs, to microcontrollers, to image sensors...etc. these things are all included as they're all ICs. So, on average, it still holds AFAIK.

    Whether or not a 14nm chip outperforms, or how much it outperforms, a 28nm one (there wasn't one for Intel, but Sandy was 32nm) is NOT what Moore's Law predicts. Other people have construed this "Law" to mean things about performance (including some guy at Intel that once said performance would double every xx months--totally wrong and not what Moore's Law states anyway), but it's not about performance and certainly not just about desktop CPUs.

    You can't say something is a "crock of $%!24" if you don't know what it's about to begin with.
  • Kutark - Thursday, August 20, 2015 - link

    Unfortunately, whether or not someone understands something has never stopped someone from speaking their mind on it. Hell, look at pretty much every election under the sun. The vast majority of people who vote in them couldn't even give you a basic rundown of the issues at hand, yet they sure do have an opinion on it...

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