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Intel Skylake review: Core i7-6700K and Core i5-6600K review

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Intel Skylake Core i7-6700K
  • Intel Skylake Core i7-6700K
  • Intel Skylake Core i7-6700K
  • Intel Skylake Core i7-6700K
  • Intel Skylake
  • Intel Skylake
  • Intel Skylake
  • Intel Skylake
  • Intel Skylake
  • Intel Skylake
  • Intel Skylake Test Setup
  • Intel Skylake
  • Intel Skylake Battlefield 4
  • Intel Skylake Bioshock Infinite
  • Intel Skylake Cinebench R15
  • Intel Skylake Dolphin Emulator
  • Intel Skylake Handbrake Video Encoding
  • Intel Skylake Mozilla Kraken Benchmark
  • intel Skylake Power Consumption
  • Intel Skylake Temperature

Summary

Our Score:

9

Pros

  • Excellent overall performance
  • Noticeable upgrade over Haswell
  • Big jump in graphics performance
  • Slightly more power efficient than Haswell
  • Excellent overclocking options

Cons

  • Needs a new motherboard and memory
  • Expensive if you don't need the overclocking
  • Graphics still not good enough for serious gaming

What is Intel Skylake?

It’s over two years since Intel last released a true update to its mainstream desktop CPU line, in the shape of its Haswell range. Due to a combination of changed priorities, lack of competition from AMD and issues with its new 14nm production process, last year’s Broadwell update never really made it to the conventional desktop arena, with it instead being prioritised for laptop and tablet form factors, such as used in the Dell XPS 13 (2015).

Instead we got a refresh of Haswell that saw clock speeds tweaked across the board. There was also the introduction of the Devil's Canyon range that included the Core i5-4690K and Core i7-4790K. However, these were again basically just a clock speed push. So, no new features, no power saving and overall a modest improvement in performance.

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A few desktop Broadwell chips were announced but few are available to buy and in fact some shops have simply not even bothered to stock them, instead waiting for the arrival of the company’s brand new line: Skylake.

Sporting a new chip design, as well as a smaller manufacturing process, compared to Haswell, the new chips should bring significant performance and power saving improvements (depending on configuration). Also, combined with their new motherboard chipsets, they’ll support more features right out the box, such as Thunderbolt 3 and DDR4 memory.

While the majority of the Skylake lineup will arrive later in the year, today sees the launch of the top of the line Core i7-6700K and Core i5-6600K, which are aimed at enthusiast users that are particularly interested in overclocking. Let’s see if they’ve been worth the wait.

Related: Windows 10 review

Intel Skylake

Intel Skylake – What’s inside?

As with Haswell and Broadwell before, Skylake denotes an overall chip design that will be used in various forms to create a multitude of different processors covering everything from high-end desktop PCs to thin and light laptops.

The full range will be extensive, but can essentially be broken down into four main families. Skylake-S are the desktop CPUs while Skylake-Y, U and H are all for mobile or embedded applications.

The Core i7-6700K and Core i5-6600K fall into the Skylake-S category, but are distinguished by a couple of key features. The K denotes that these chips have unlocked multipliers, which means they are far more open to being overclocked. They also lack the L4 cache of some of the lower chips, as the integrated graphics is less of a focus, with the assumption being that most users of these processors will have discrete graphics cards.

Otherwise, the core improvements in Skylake benefit the whole range, and with this launch the improvements should be even greater than we’d normally expect.

It all harks back to Intel’s traditional tick-tock release schedule where one year – the tick – the chip range is based on essentially the same design as the year before but with a smaller manufacturing process. Then the next year – the tock – is based on the same manufacturing process, but with a new design.

Related: DirectX12 vs 11 – How DX12 will transform PC gaming on Windows 10

Intel Skylake

The new design brings performance and power saving innovations along with new features, while the smaller manufacturing process tends to reduce power consumption and increase potential clock speed. Plus it allows Intel to fit more chips on each wafer of silicon, making them cheaper to produce.

This has gone on for years and is why we’ve tended to see processor ranges named in pairs, such as Sandy Bridge and Ivy Bridge, Haswell and Broadwell and now Skylake followed by Kaby Lake. Each pair indicating the same overall design, with the second name in each pair being the smaller version.

That brings us to Skylake and the fact that Broadwell essentially never arrived for the desktop. As such you’re getting the die-shrink of Broadwell and the new design of Skylake, which should add up to a decent leap in performance/power saving over Haswell.

Specifically, where Haswell was built using a 20nm process, Broadwell and Skylake use a 14nm process. We’ve seen signs of the benefits of this 14nm process in Broadwell laptop processors, such as in the new line of Apple MacBooks, as well as the new Core M chip design, which has brought a new level of performance to the ultra low-power laptop market, as seen in the Asus Zenbook UX305.

Aside from its new manufacturing process, Intel has kept fairly quiet on exactly what’s under the hood of Skylake, with further details about the new design expected to be revealed at the Intel Developer Forum (IDF) from Monday 17th August onwards.

As such this review really boils to the two announced chips and what they can do.

The Core i7-6700K and Core i5-6600K

While the two new K-series processors we’re looking at today are the flagships of the Skylake range, it’s worth noting that they aren’t the flagship processors in Intel’s overall range.

Even putting aside the company’s Xeon server chips, there are also the Haswell-E and Ivy Bridge-E chips to consider. Essentially consumer versions of Xeon chips, these are based on older overall designs but pack in more physical processing cores.

Whereas the Skylake range tops out at four physical cores (some with hyperthreading where it appears to the system like it has 8 cores), the Haswell–E range has six and 8 core variants that also have hyperthreading, so they can deal with 12 and 16 threads respectively. That makes them still the fastest multi-threaded workload processors for the foreseeable future.

However, they’re priced accordingly and are also supported by more expensive motherboards. If you’re looking to make a video encoding rig or run multiple graphics cards then they’re still the best bet, but for more general purpose use with a single graphics card, Skylake is the way to go.

Intel Skylake

The Core i7-6700K, then, is a four-core chip with hyperthreading that runs at 4.0GHz, with a boost clock of up to 4.2Ghz – that’s where the chip will self-overclock one or more cores on demand and where possible, without exceeding the overall thermal design of the chip. It also packs in 8MB of L3 cache and supports up to 16 PCI express 3.0 lanes and has two memory channels with a maximum rated clock speed of DDR4-2133 and DDR3-1600.

Meanwhile, the Core i5-6600K drops the hyperthreading and starts off at 3.5GHz with a boost of up to 3.9GHz. It also drops to 6MB of L3 cache but is otherwise the same.

Both chips are rated at 91W TDP, which actually puts them above the 88W Core i7-4790K and Core i5-4690K.

andyvan

August 5, 2015, 1:05 pm

Editor's note: Pretty graphs are coming very soon. Minor internet fails on our end.

Dead Words

August 5, 2015, 4:28 pm

Looking forward to them.
What's the chance of Intel releasing a more powerful i7 processor using the Skylake architecture that brings more cores and more power for gaming?
It looks to me like Haswell and Broadwell were the two generations focused on mobile processors like laptops and tablets, but that Skylake and Koby Lake are going to once again put a lot of focus on desktops (possibly because of the release of Windows 10 and the expected (hopeful) increase in desktop sells?) so it makes sense to me for Intel to update their most powerful processors using the smaller manufacturing process and the new architecture.

Dead Words

August 5, 2015, 4:31 pm

Hey I'm liking the pretty graphs.

Dead Words

August 5, 2015, 4:35 pm

I love how the Core i3 managed to get a higher framerate with Battlefield 4 on ultra graphics.
Computer hardware is absolutely fascinating. I'm way more into the software side of things but I'd still love to learn how each piece corresponded with the others and how it all fit together.

LeeTronix

August 5, 2015, 5:18 pm

Spot on review very well put together.

The new processors will no doubt be great for gaming enthusiasts but also people needing to perform high end rendering or graphic processed scenarios and with its core management.

Ed

August 6, 2015, 11:00 am

Thanks, always appreciated.

MattMe

August 6, 2015, 2:20 pm

It's interesting to see that your review sees higher improvement over older gen CPUs than other sites I've read similar reviews on.

Also, definitely worth noting that the integrated graphics on these chips are likely to be quite low-spec compared to other chips released later due to these being specialised designed for being overclocked and run with a separate GPU.
It'll be interesting to see how the more mainstream CPU's integrated graphics perform.

Jim

August 6, 2015, 4:49 pm

Do you have graphs of the temperatures and power consumption? I'm interested in seeing the power draw difference between Haswell i3/i5 and Skylake i5.

Habib

August 9, 2015, 11:13 pm

I am wondering if the integrated graphic of i7-6700 is good enough for streaming from internet in 4k resolution? (NO GAMING)

Ed

August 11, 2015, 11:05 am

Yes, that shouldn't be a problem.

Alfihar Woodfridge

August 12, 2015, 9:03 pm

I only don't agree with the "Noticeable upgrade over Haswell", they perform almost the same nothing noticeable at all performancewise over haswell, specially when they are already clocked 100mhz higher than 4xxx k series and show a tiny bit higher scores.
Its like an eco-friendly 4k series with DDR4 compatibility and 5fps better integrated graphics.

Besides that nice review.

Brandon Hart

August 18, 2015, 5:31 pm

In my opinion, you'd have been better off using a higher-end CPU for the discrete graphics in your test. The 290 is obviously not bottlenecking any of those CPUs or maybe that's what you wanted?

Comandante ÑOÑARDO

September 14, 2015, 9:32 pm

According to this, Battlefield 4 is well optimized for dual core processors and bad optimized for quad core processors. Measure mistake or true fact?

Kordanor

October 25, 2015, 3:40 pm

Great Benchmarks. Nice to see the "factual" relevance of CPU difference in games. Stressing CPU by minimal graphics settings is fine. But it doesn't apply to the real world.
In lots of other Benchmarks it looks like one CPU to the next would make a similar boost as graphics cards which of course isn't the case for games. In this benchmark for example it's clearly visible that the difference from 6600k to 6700k is less than 1.5% in actual gameplay.

billy smith

November 8, 2015, 6:08 pm

I am running i core 5,windows 10 it is crashing when I scroll down with 2 windows open .It seems not to crash when using chrome browser just bought this desktop amazing ,here is the best part I went from Vista with all its issue at first to 10 great timing!!

laurens

December 16, 2015, 6:52 pm

That just means it is not made to take advantage of multiple cores. A dual core that scores 6000 point is faster per core than a quad core: 6000 / 2 cores = 3000 per core, 6000 / 4 cores = 1500 per core.

Brad B

December 18, 2015, 10:00 pm

You need to update the graphics.

Brad B

December 18, 2015, 10:02 pm

The processors will automatically switch off and boost the ones that are on. So, 4-turn off two 2.7Ghertz. Then the two left will overclock to 3.4Ghertz.

Brad B

December 18, 2015, 10:04 pm

Yes, but you are being misleading a quad core can turn off processors and start overclocking which means it will go 2.7 Ghertz then can boost two processors to a 3.4. Which makes certain tasks more efficient by turning off and on cores.

TheRealMrBlobbysRevenge

December 19, 2015, 9:52 pm

Geez, I look at the USD prices listed above and then I compare to the GBP prices...FFS, the UK is getting ripped off! :(

billy smith

December 20, 2015, 12:16 pm

That is one of the first things I checked all drivers were updated

Brad B

December 21, 2015, 10:57 am

I only had an issue for the first couple days and after all updates and everything no problems. I can't remember if I did anything special but doubtful. I think it was just the Intel(R) Driver Update Utility I used.

Brad B

December 22, 2015, 8:07 am

Did you get it to work?

billy smith

December 22, 2015, 5:28 pm

No ,the techs from ASUS put the damn thing into a blue screen of death .I called again and still they could not unlock the machine .So it went back think god I used Amazon ,Amazon made AZUS refund my money back so I will stay loyal to Amazon .ASUS was not wanting to work with me at all. I read the have a history of not backing their machines causing lots of folks stressful times when they were totally at fault .

I bought a Dell from Nebraska Furniture mart so far so good .

Brad B

December 23, 2015, 1:52 pm

All I can say is that I did have the problem and tried to report it to ASUS but they ignored me. I figured out that some of the devices were not working correctly and fixed them. Once i fixed them the problem was resolved. I did post a review and included that information in the review so everyone knows that it does work but if you are an average consumer you might not understand how to fix it so it loses its value.

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