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
POST A COMMENT

477 Comments

View All Comments

  • SkOrPn - Tuesday, December 13, 2016 - link

    Well if you were paying attention to AMD news today, maybe you partially got your answer finally. Jim Keller yet again to the rescue. Ryzen up and take note... AMD is back... Reply
  • CaedenV - Wednesday, August 5, 2015 - link

    Agreed, seems like the only way to get a real performance boost is to up the core count rather than waiting for dramatically more powerful single-core parts to hit the market. Reply
  • kmmatney - Wednesday, August 5, 2015 - link

    If you have an overclocked SandyBridge, it seems like a lot of money to spend (new motherboard and memory) for a 30% gain in speed. I personally like to upgrade my GPU and CPU when I can get close the double the performance of the previous hardware. It's a nice improvement here, but nothing earth=shattering - especially considering you need a new motherboard and memory. Reply
  • Midwayman - Wednesday, August 5, 2015 - link

    And right as dx12 is hitting as well. That sandy bridge may live a couple more generations if dx12 lives up to the hype. Reply
  • freaqiedude - Wednesday, August 5, 2015 - link

    agreed I really don't see the point of spending money for a 30% speedbump in general, (as its not that much) when the benefit in games is barely a few percent, and my other workloads are fast enough as is.

    If Intel would release a mainstream hexa/octa core I would be all over that, as the things I do that are heavy are all SIMD and thus fully multithreaded, but I can't justify a new pc for 25% extra performance in some area's. with CPU performance becoming less and less relevant for games that atleast is no reason for me to upgrade...
    Reply
  • Xenonite - Thursday, August 6, 2015 - link

    "If Intel would release a mainstream hexa/octa core I would be all over that, as the things I do that are heavy are all SIMD and thus fully multithreaded, but I can't justify a new pc for 25% extra performance in some area's."

    SIMD actually has absolutely nothing to do with multithreading. SIMD refers to instruction-level parallellism, and all that has to be done to make use of it, for a well-coded app, is to recompile with the appropriate compiler flag. If the apps you are interested in have indeed been SIMD optimised, then the new AVX and AVX2 instructions have the potential to DOUBLE your CPU performance. Even if your application has been carefully designed with multi-threading in mind (which very few developers can, let alone are willing to, do) the move from a quad core to a hexa core CPU will yield a best-case performance increase of less than 50%, which is less than half what AVX and AVX2 brings to the table (with AVX-512 having the potential to again provide double the performance of AVX/AVX2).

    Unfortunately it seems that almost all developers simply refuse to support the new AVX instructions, with most apps being compiled for >10 year old SSE or SSE2 processors.

    If someone actually tried, these new processors (actually Haswell and Broadwell too) could easily provide double the performance of Sandy Bridge on integer workloads. When compared to the 900-series Nehalem-based CPUs, the increase would be even greater and applicable to all workloads (integer and floating point).
    Reply
  • boeush - Thursday, August 6, 2015 - link

    Right, and wrong. SIMD are vector based calculations. Most code and algorithms do not involve vector math (whether FP or integer). So compiling with or without appropriate switches will not make much of a difference for the vast majority of programs. That's not to say that certain specialized scenarios can't benefit - but even then you still run into a SIMD version of Amdahl's Law, with speedup being strictly limited to the fraction of the code (and overall CPU time spent) that is vectorizable in the first place. Ironically, some of the best vectorizable scenarios are also embarrassingly parallel and suitable to offloading on the GPU (e.g. via OpenCL, or via 3D graphics APIs and programmable shaders) - so with that option now widely available, technologically mature, and performant well beyond any CPU's capability, the practical utility of SSE/AVX is diminished even further. Then there is the fact that a compiler is not really intelligent enough to automatically rewrite your code for you to take good advantage of AVX; you'd actually have to code/build against hand-optimized AVX-centric libraries in the first place. And lastly, AVX 512 is available only on Xeons (Knights Landing Phi and Skylake) so no developer targeting the consumer base can take advantage of AVX 512. Reply
  • Gonemad - Wednesday, August 5, 2015 - link

    I'm running an i7 920 and was asking myself the same thing, since I'm getting near 60-ish FPS on GTA 5 with everything on at 1080p (more like 1920 x 1200), running with a R9 280. It seems the CPU would be holding the GFX card back, but not on GTA 5.

    Warcraft - who could have guessed - is getting abysmal 30 FPS just standing still in the Garrison. However, system resources shows GFX card is being pushed, while the CPU barely needs to move.

    I was thinking perhaps the multicore incompatibility on Warcraft would be an issue, but then again the evidence I have shows otherwise. On the other hand, GTA 5, that was created in the multicore era, runs smoothly.

    Either I have an aberrant system, or some i7 920 era benchmarks could help me understand what exactly do I need to upgrade. Even specific Warcraft behaviour on benchmarks could help me, but I couldn't find any good decisive benchmarks on this Blizzard title... not recently.
    Reply
  • Samus - Wednesday, August 5, 2015 - link

    The problem now with nehalem and the first gen i7 in general isn't the CPU, but the x58 chipset and its outdated PCI express bus and quickpath creating a bottleneck. The triple channel memory controller went mostly unsaturated because of the other chipset bottlenecks which is why it was dropped and (mostly) never reintroduced outside of enthusiast x99 quad channel interface.

    For certain applications the i7 920 is, amazingly, still competitive today, but gaming is not one of them. An SLI GTX 570 configuration saturates the bus, I found out first hand that is about the most you can get out of the platform.
    Reply
  • D. Lister - Thursday, August 6, 2015 - link

    Well said. The i7 9xx series had a good run, but now, as an enthusiast/gamer in '15, you wouldn't want to go any lower than Sandy Bridge. Reply

Log in

Don't have an account? Sign up now