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
Comments Locked

477 Comments

View All Comments

  • xxxGODxxx - Saturday, October 31, 2015 - link

    Hi guys I would like to know whether I should buy the 6600k with a z170 mobo at $417 or should I buy a 3930k with a x79 mobo at $330? I'm not too sure if the extra IPC of the 6600k is enough to warrant the extra $87 over the 3930k especially since I will be overclocking the cpu and I will be gaming on a r9 390 (maybe I will add one more 390 in the future) at 1440p.
  • Toyevo - Wednesday, November 25, 2015 - link

    Even now I hesitate at updating a Phenom II X4 945. The Samsung 950 Pro pushed me over the line, and with it the need for PCIe M.2 only available in recent generations. There's no holy grail in CPUs, only what's relevant for each individual today. Of several other systems I have, none demand any change yet. On the Intel side my 2500K (and up) I wouldn't bother with even Skylake. With AMD my FX6300 (and up) are more power hungry but entirely adequate. And our E5-2xxx servers sit on Ivy Bridge until early 2017.

    What does all this mean? Not a lot.. In the same way many of you see Skylake as a non event, I equally saw Broadwell and Haswell as non events. 20 years ago the jumps were staggering, overclocking wasn't nearly as trendy, nor as straight forward, but entirely necessary, the cost of new hardware prohibitively expensive. The generations were so definitive and fast back then.
  • i_will_eat_you - Saturday, December 12, 2015 - link

    This is a good review, especially the look at memory latency. The 4690K is left out however from a lot of benchmarks. If you include that then I don't see much of an attraction to skylake. There is also the concern about the new rootkit support skylake introduces with protected code execution. This is not something I see being used for the good of the consumer.

    My one gripe is the lack of benchmarks for intense game engines (simulations, etc). Total war is there which is a step forward but I'm not sure if that benchmark really measures simulation engine performance.

    If you take games such as Sins of a Solar Empire or Supreme Commander then they have a separate thread for graphics so tend to maintain a decent frame rate even when the game engine runs at a crawl. The more units you add to the map and the more that is going on the slower it goes. But this is not in FPS. It means that ordering a ship across the solar system might take 10 s when there are 1000 units in the game but 5 minutes when there are 100000 units in the game. I would love to see some benchmarks measuring engine performance of games such as this with the unit limits greatly increased. It is a bit of a niche but many sim games (RTS, etc) scale naturally which means you can increase the unit limit, map size, AI difficulty, number of AIs, etc as your hardware becomes more powerful.

    This is especially relevant with CPUs such as the broadwell which might gain a big advantage each game loop processing the very large simulation engine dataset.
  • systemBuilder - Tuesday, July 19, 2016 - link

    Wow your review really sucked. Where are the benchmarks for the i5-6600k? Did you forget?
  • POPCORNS - Friday, August 19, 2016 - link

    To me, It doesn't matter if there's no IPC improvement over Sandy Bridge, Ivy Bridge or Haswell,
    Because I've upgraded from a Wolfdale Celeron (E3300) to a Skylake (6700K), lol.
  • oranos - Thursday, December 29, 2016 - link

    This article seems to be confused. DDR4 brings more sustained framerates for higher resolutions (especially 4k). Really a waste of time doing a 1080p comparison.
  • oranos - Thursday, December 29, 2016 - link

    if you wanted to do a proper test for DDR4 gaming performance you should run a 6700K and GTX 1080 minimum and run multiple games in 4K for testing.

Log in

Don't have an account? Sign up now