Today, Intel has taken the wraps off Skylake, the sixth-generation 14nm Core architecture that follows on from Broadwell. Only two desktop chips are being released today: the high-end Core i7-6700K and Core i5-6600K. The "full" Skylake unveil, including a detailed breakdown of architectural changes and the full SKU line-up (including the all-important laptop parts), will occur at IDF on August 18.

Skylake is technically two full jumps ahead of Haswell, which was released in 2013. For the last decade, Intel has released new processors on a yearly basis, in accordance with its Tick-Tock cadence: one year (the tick) sees a process shrink to smaller transistors and better efficiency, the next year (tock) ushers in a brand new microarchitecture. Intel successfully stuck to the Tick-Tock model until Broadwell, where the shrink from 22nm to 14nm was heavily delayed.

The Broadwell desktop chips never saw the light of day in 2014, and the firm only just managed to officially stick to its plans by releasing some low-power 14nm Broadwell Core M processors at the tail end of the year. Meanwhile, on the desktop, Intel instead released a refresh of its existing 22nm Haswell processor line—the Devil's Canyon Core i7-4790K and Core i5-4690K—which offered nothing more than higher clock speeds over the earlier Haswell models.

Desktop Broadwell chips were eventually released in June 2015, but it was an incredibly low-key affair. These desktop parts—the Core i7-5775C and friends—only had two notable features: a 65W TDP, and Intel Iris Pro 6200 integrated graphics. Unfortunately, when it came to performance, the top-end Broadwell chip was handily beaten out by the previous-gen Core i7-4790K, and it had lower default and turbo clock speeds as well. Although the move to 14nm has allowed for improved battery life in some mobile platforms, the desktop chips were disappointing.

Now, just two months later, Broadwell is being swept fully under the rug and superseded by Skylake, a brand new 14nm chip that promises to actually be faster than Haswell.

Before we get into the testing, let's briefly run through the high-level changes in Skylake and its shiny new companion chipset, Sunrise Point.















The new Skylake chips

The new high-end desktop processors are the Core i7-6700K and Core i5-6600K, both of which are quad-core chips. As with previous generations, the Core i7 features hyper-threading, while the Core i5 does not. This technology creates two virtual processors for every physical CPU core, so the operating system sees eight cores, and multi-threaded software takes better advantage of all available CPU resources.

The Core i7-6700K has a default clock speed of 4GHz and a turbo frequency of 4.2GHz, while the Core i5-6600K has a default clock speed of 3.5GHz and a turbo frequency of 3.9GHz. Both chips run at a TDP of 91W, slightly higher than the 88W of the Devil’s Canyon chips, with a voltage of 1.2V. There’s 8MB of level 3 cache in the Core i7-6700K, with 6MB in the Core i5-6600K.

A new socket type has been introduced called LGA1151, making Skylake processors physically incompatible with Haswell motherboards. Therefore if you want one of the chips, you’ll need to fork out for a new board as well. Coolers are 100 percent compatible though, if they already support LGA1150 or LGA1155.

The Core i7-6700K, which should be available from your favourite component retailers today, will cost $350 (about £300 in the UK and €350 in the Eurozone). The Core i5-6600K, also released today, costs $243 (~£200/€250). Intel only ever gives the MSRP in dollars, so actual pound and euro pricing will be down to the retailers. Intel has kept its pricing roughly in line with the previous generation, with a price difference of around $100 between the Core i5 and Core i7.

As before, the K-series Skylake chips feature unlocked multipliers, so enthusiasts can overclock their processor just by changing the multiplier in the BIOS (UEFI), and by increasing the voltage for the higher speeds.

Haswell introduced a second way to adjust the clock frequency of a K-series CPU: by changing the base clock (BCLK). Normally this value is 100MHz, but Haswell offered a number of preset straps: 100MHz, 125MHz and 166MHz. Skylake goes further, allowing you to alter it with fractional increments: setting the base clock to 112.5MHz with a 40x multiplier results in a CPU speed of 4.5GHz, for example. This will be a welcome feature for overclockers and high-performance enthusiasts looking to get the most out of their chips.

S-series Skylake desktop chips will follow soon, with locked multipliers and lower prices, aimed at more affordable systems, and there will certainly be a range for laptops and tablets too.

Sunrise Point: An exciting new chipset

Along with a new microarchitecture and socket, there's also a new chipset called Sunrise Point. Sunrise Point is the basis for Intel's 100 Series of chipsets, which range from the H110 on the low end, with the most restrictive feature set, up to the Z170 at the high end, with all of the various bells and whistles.

The biggest change with Sunrise Point is the introduction of PCI Express 3.0 support, with 20 lanes (on the Z170) each running at 8 GT/sec, which provides a lot more bandwidth for PCIe storage devices. An M.2 solid-state drive such as the Kingston Hyper X Predator or Samsung SM951 connected to a Z170 motherboard has four dedicated PCIe 3.0 lanes, which means it has up to 32Gbps of bandwidth. This is a great improvement over both 6Gbps SATA and M.2 on Z97 motherboards, which was limited to just two PCI Express 2.0 lanes.

Up to 10 USB 3.0 ports are available for inclusion on motherboards, although the newer 10Gbps USB 3.1 standard is notably missing. USB 3.1 ports are still present on some motherboards, however, thanks to third-party controllers. Expect high-end deluxe boards to offer USB 3.1 support, with more affordable boards sticking with USB 3.0.

Thunderbolt 3 is an optional extra as well, via Intel’s Alpine Ridge Controller. It now runs at 40Gbps and comes with a Type-C USB connector. This connector was present on the Asus Z170 Deluxe (the motherboard we used for this review), but the controller was not, so it doesn’t support Thunderbolt 3. Asus told us that a future motherboard will add support, and presumably other deluxe motherboard models will follow suit.

For more details on the Sunrise Point chipset, hit up our detailed explainer.

DDR4 hits the mainstream

DDR4 memory isn’t exactly new—it debuted with Intel’s Haswell-E processors and the X99 chipset last year—but this is the first time a consumer platform has offered the updated memory technology. DDR4 comes in speeds that currently range from 2133MHz to 3200MHz, and CAS latencies hovering around 16ns. DDR4 uses 288 pins, so it won’t fit into the 240-pin slots on a DDR3 motherboard. It also has a lower voltage, running at 1.2V, compared with 1.5V for regular DDR3 memory.

Prices are currently slightly higher too, increasing the overall cost of a Skylake PC over an equivalent Haswell build. From a quick look at online retailers, 16GB of DDR4 only costs about 33 percent more than 16GB of DDR3, so the overall increase to the cost of a PC build is slim.

Officially, Skylake also supports 1.35V DDR3, which is sold as DDR3L memory. Intel imagines DDR3L being used in low-cost systems, but in motherboards aimed at enthusiasts it’s unlikely any manufacturer will choose it over DDR4. DDR3 and DDR3L are not at all the same, so there is no chance any Skylake platform will work with existing 1.5V memory in your computer.

In addition to faster speeds, a potential benefit of DDR4 is increased capacity per DIMM module. In the consumer space, unregistered DDR3 DIMMs have generally maxed out at 8GB—so with a motherboard with four memory slots the most you could ever have is 32GB. It may sound a lot, but with 16GB now a baseline for any high-performance PC, this fundamental limit has almost been reached. There have been rumblings of unregistered 16GB DDR3 DIMMs over the past couple of years, but they haven't yet arrived on the market.

It's also important to note that, while Haswell-E and X99 supported quad-channel operation, Skylake and Sunrise Point will only do dual-channel. Presumably Skylake-E will again bring back a quad-channel integrated memory controller.

Intel HD Graphics 530, and other GPU stuff

With every generation of Core chips, Intel has placed more and more emphasis on integrated graphics, and Skylake is no different. The integrated GPU that comes with Skylake is called Intel HD Graphics 530, and is DirectX 12 compatible. The GPU's clock speed boosts to 1150MHz, and some models (not the HD 530) will likely include a quantity of embedded DRAM (eDRAM). Intel isn't yet talking about the new GPU's architecture in detail, so we can't offer any more specifics at this point; specifics will probably come on August 18 at IDF.

Overall, don't expect Intel HD Graphics 530 (or the inevitable "Iris" version) to allow you to play modern 1080p games at ultra detail levels, but 720p on high or medium details ought to be possible.

One aspect of Skylake processors that hasn’t changed is the number of PCI Express 3.0 lanes, which is still set at 16. This allows for a single PCIe graphics card to operate at x16 speeds, or a pair in SLI or CrossFire to operate at x8. For more graphics lanes, you’ll need a Haswell-E processor (the top-end 5960X has a grand total of 40 PCIe lanes)—although moving to the X99 chipset is of questionable value if it’s just for SLI or CrossFire use.

Skylake architecture: What we know so far

Unfortunately, Intel isn't yet talking about the low-level architectural changes between Haswell and Skylake, instead waiting until the full range of Skylake chips are available. For now, though, we can run through some things that Intel has previously said about Skylake, and some reliable rumours that have popped up on the Web.

The all-important direct media interface (DMI) connection between the chipset and processor has been upgraded to DMI 3.0, supporting up to 8 GT/sec.

One of the biggest and most important (unconfirmed) rumours is that Skylake has abandoned the fully-integrated voltage regulator (FIVR), which was first introduced with Haswell but proved problematic for the 14nm Broadwell die shrink. With the Broadwell H, U, and Y SKUs, Intel moved the platform controller hub (PCH) onto the chip package; for the mobile Skylake parts (i.e. not S or K), it is expected that Intel will go one step further and integrate the PCH onto the CPU die itself. This will move the mobile-oriented Skylake chips one step closer to becoming full SoCs.

This still leaves many unanswered questions about exactly has been added and removed from Intel's new chips, especially since Skylake has an increased overall TDP over Haswell, despite a process shrink. Some answers will probably emerge from benchmarking and analysis, while others will have to wait for Intel's full reveal later this year.

And now, without further ado, let's review the new flagship Skylake chip: the Core i7-6700K.

Listing image by Orestis Bastounis