Skylake Deep Dive
Taking us from that blasted 22nm architecture down to 14nm was an incredible feat. But it was too little, too late. Ultimately, the little chip paid the price, doomed to retire to an early death. A victim of its own architecture’s difficult production methods.Broadwell’s glorious sacrifice, however, has given us one phenomenal gem – Skylake. If the X99 chipset and Haswell-E was the premium-grade reboot that PC enthusiasts needed, it’s safe to say that Z170 and Skylake is about to do the same for the rest of us lowly four-core lovers. And let’s face it, we’ve sorely needed it.The last three generations of Intel CPUs have hardly seen a vast improvement over the original Sandy Bridge chips, and it’s about time we were given CPUs that mopped the floor with that dusty old dog. Yes, Intel’s cores may generally run rings around the competition when it comes to compute performance, but a 5 per cent performance increase and 10 per cent power reduction, year after year, just isn’t exciting enough to warrant tattooing the Intel logo on the inside of our thighs. Not just yet.Regardless of how it likes to name its early morning glow chipsets, Intel needs to knock this one out of the park. And although it’s pretty much cemented itself in the world of enthusiast-grade CPUs, another 5 per cent performance boost just isn’t that interesting, especially when most games currently struggle to utilise anything more than four cores anyway. Hell, we’d still recommend the i5-2500K if it was still available for sale.So what was it that kept Intel behind for so long? What do these chips represent to us? And what shiny new features will it bring to the table? Read on to find out what we discover in our in-depth report.Let’s start with the basics. At this point, we have the Intel Core i5-6600K and the Core i7-6700K – the premium overclocking CPUs for the enthusiast users. These are the flagship models of Intel’s consumer brand. Processors that, by their very nature, are designed to be pushed to the limits in the hunt for number crunching, benchmark-rendering, overclocking perfection.But what does Skylake bring to the table that Haswell didn’t? Well, a 14nm processor for starters. Similar to the now-redundant Broadwell, yet a lot more promising. Intel has dropped the FIVR (Fully Integrated Voltage Regulator) from the CPU die and left voltage control entirely down to the motherboard manufacturers. This allows aftermarket partners to control how they supply power to each individual voltage controller located onboard the chip. What’s exciting about this is how much variance we may start to see in the motherboard market once again. It’s an area where, for a long time, it’s been very difficult to differentiate between or even justify the cost of a £300 board over a £100 one. It might make choosing your motherboard about more than just buying the prettiest one for your budget. And that’s fantastic, especially for competition’s sake.On top of all this loveliness, the Z170 chipset has a vastly expanded array of storage options – including Intel’s new U.2 PCI Express connector, an additional 12 PCIe lanes to allow greater performance when running NVMe, and PCIe M.2 drives (an upgrade from gen2 to gen3). There’s also continued support for six SATA 6Gb/s devices, up to 10 USB 3.0 ports and 14 USB 2.0 ports. Rather surprisingly, however, there isn’t any native support for USB 3.1 (both Type A and Type C). Intel has stated that it’s banking on Thunderbolt 3 being the more appealing solution to this particular platform. Although this seems a little short-sighted going forwards, only time will tell whether that will hold true or not.Who knows, maybe 3D Xpoint memory sticks will be powered by Thunderbolt and Intel will become our silicon overlord.But the biggest and most exciting feature by far is the support for DDR4 RAM, the final advancement beyond the limited 2,400MHz DDR3 band. Z170 motherboards will support up to 64GB of memory, from 2,400MHz all the way up to 4,000MHz and beyond, advancing the ageing platform far past that of its Broadwell and Haswell cousins.But don’t fret if DDR4 prices are still a little too steep, and you have a few DDR3L RAM sticks kicking about, Skylake is backwards compatible. Albeit only with the low-voltage economy version, as opposed to the last platform’s DDR3 offerings. That means that if you’d rather just use a DDR3L-enabled motherboard, you can do just that. But saying that, these boards do seem to be few and far between. The only manufacturer we know of that has boards with this feature for the foreseeable future is Biostar, a company that didn’t exactly score very highly in its last review.If you’re dipping into the funds to build a new rig, you really should be looking at DDR4. Prices have dropped by roughly half since they were launched in October last year, which means you’re only paying around £20 extra for the same capacity of RAM at a far higher frequency than you once were.Still not interested? Do you consider yourself a bit of a speed freak, but memory just doesn’t float your boat? Well, ladies and gents, we have one last nugget of juicy information for you – that’s the inclusion of PCIe Raid 0, 1 and 5 support, allowing end users to RAID multiple NVMe drives together.This has the potential to increase transfer read and write speeds all the way up to 3,500MB/s and beyond, approximately six times faster than your traditional SSD.Skylake’s new architecture has been painstakingly woven from Intel’s manufacturing plants and engineering genius. Having to drop Broadwell, even just to make its production deadlines, Skylake is the first widely available 14nm CPU microarchitecture.It’s a chip that’s situated in the brand-spanking new 1151 socket (yes, one whole extra pin), alongside the Z170 chipset. Although not the consumer’s first access to a 14nm chip, it’ll be the most commonly sought-after processor line going forward, the go-to buy for us PC enthusiasts, overclockers and system builders looking for the best mid-range processors for our towers of power.To build a processor like Skylake, you have to start from the ground up, and that’s with the silicon. Essentially, a wafer-thin slice of computing crystalline goodness, silicon provides the basis for what the CPU will become, before it’s cut out and embedded into the CPU superstructure that we’re all so familiar with. Utilising a 193nm ArF lithography (basically a highpowered laser), Intel has to etch in all of the details for each and every processor, from each transistor upwards, essentially crafting every detail that makes a CPU a CPU.The difficulty lies in the lithography itself. The laser in its most minute form is 193nm wide. To put that into perspective, the width of a human hair is 75,000nm across. So, to get that tiny beam of light small enough to even create one single transistor, it’s necessary to utilise a variety of different technologies and optics to split the beam into even more ridiculous molecular sizes without necessarily losing any of the additional power that comes from the original beam. The smaller you go, the more difficult it becomes to split the laser down further. Ultimately, this is why it’s taken Intel so long to go from the 22nm die size to Unm, and thus why Broadwell has had such a brief (and rather unexciting) shelf life. We can only hope that this will not be the case for the 10nm chips.But alas, not all is lost. If it wasn’t for Broadwell’s sacrifice, we wouldn’t have Skylake. Thankfully, it’s here and on schedule, ensuring Intel’s latest flagship dodged a similar fate. For release dates we can only speculate at this point, but rumour has it the full desktop lineup should be available by the end of this year, with mobile laptop processors making it to market by early 2016. Again, speculation and rumour on our part.DDR4 memory is a crucial part of Intel’s marketing strategy here. Although it’s the next natural progression, the launch price was more than enough to put most people off their dinner. Fortunately, kits have been around since October 2014 and have slowly dropped in price since then with the launch of the extreme edition processors. With Skylake’s release (and dual channel support) comes a wide variety of dual-channel kits at almost a comparable price point to DDR3. If you’re still unsure what memory to choose, however, don’t worry. Intel has you covered. Memory kits from the likes of Crucial, Corsair, G. Skill, Patriot, Kingston and Adata have all been approved by Intel, just to keep you safe of mind.The Z170 motherboards, on the other hand, have been making the rounds for quite some time now, debuting with a wide variety of manufacturers showing off their long-awaited products at Computex, back in June. And man, do they look good! Most mainstream board partners have had these things ready since last Christmas (or thereabouts), so if you must have the latest hardware, or are thinking it’s time for an upgrade, you’ll be more than spoilt for choice.So, how does Skylake actually perform? Well, it isn’t the absolute be-all-and-end-all of chip advancements. If you’re only one generation behind, with Devil’s Canyon, you’ll only see around a 10–15 per cent improvement in benchmarks and rendering times, clock for clock.In Cinebench, we saw an outright 11 per cent increase in performance over Intel’s Core i7-4790K. Not too shabby to say the least, but not exactly beyond the realms of what we expected.What is interesting is how far we can push the powerful four core. Skylake’s overclocking potential is well documented as being far greater than that of its last three predecessors. And once we cranked our chip all the way up to 4.8GHz (a conservative clock, admittedly), we actually managed to push this core to perform just a little under that of an i7-5820K extreme edition processor at stock. Interested? You should be. It’s certainly not impossible to get this processor even higher than that. Reports have come in of people clocking 5.2GHz on air alone, all dependent on the motherboard more so than ever. In fact, we managed to achieve these benchmarks on an entry-level £100 Asus motherboard.All in all, this chip provides us with a very unique insight into what the 14nm processor series can do. But let’s cut to the chase. Why is 11 per cent good? Is it really worth it? Well, consider it this way. If it’s 10 per cent better than an i7-4790K, it’ll be roughly 20 per cent better than a 4770K, and 30 per cent better than a 3770K, and so on.If you’re still stuck on the everfaithful Sandy Bridge architecture [like some of our writers here are… *cough*], then this might be the perfect time for you to upgrade that CPU and take advantage of all of those additional chipset features and processing power.When it comes to literal power consumption, Skylake stands head and shoulders above the rest. We decided to build a basic test system to give the new girl a run for her money. It consisted of an Nvidia GeForce GTX 980, four sticks of Kingston HyperX memory, one 240GB Samsung Evo and a more traditional 2TB Seagate something or other. Under load (Prime 95 & Furmark), the rig pulled a total of 340W from the wall, utilising only half of the 750W power supply we had it running on. If nothing else, these chips will be fantastic for small form-factor builds and Steam Machines. Hell, if you really wanted to, you could run SLI on a 750W power supply with little-to-no worries at all.The biggest area of improvement for Intel has been in the integrated graphics department. That may not mean much for those of you buying into the K-line processors, as you’ll probably also be investing in a dedicated GPU. However, utilising DirectX 12 to leverage the CPU effectively could improve frame rates considerably in games. That may not be so beneficial for Twitch and streaming enthusiasts, but it harks back to what AMD was trying to implement with its Mantle API, allowing Intel to carefully leverage the processing power for what computational tasks each core is better suited to handling.Inherently, this generation of chips is vastly different to Haswell and the Devil’s Canyon remit that we received last year. Primarily, this is down to Intel’s decision to remove the FIVR from the chip design.The FIVR, or Fully Integrated Voltage Regulator, was a component piece of the CPU found in any previous generation of Intel processor. Its sole purpose was to regulate and control the overall voltage that went directly into each part of the compute portion of the CPU, such as the DRAM controller, and the VCore. By removing this, Intel has handed voltage control to the motherboard manufacturers. This means that, instead of a standardised level of voltage operating across the entire platform, it’s now possible for board partners to implement specific voltages for each of those compute portions we mentioned earlier.But are they cooler than Devil’s Canyon? Skylake is quite cold, no doubt partly due to the removal of the FIVR we mentioned earlier. This enables you to ramp up the core clock frequency considerably, without worrying about thermally throttling the chip. But you’re still going to need an aftermarket cooler for the majority of your overclocking attempts, as it will provide a great deal more headroom when trying to achieve those higher clockspeeds.In our testing, we found the Core i7-6700K to be a solid 3–4°C cooler than the Devil’s Canyon refresh under load. And although Intel has promised to reimplement the FIVR, this doesn’t seem likely to happen until the iteration after Kaby Lake, known as Ice Lake. All in all though, we’re not too sure whether losing the FIVR is a bad thing or not.Another change that’s come with Skylake is the ability to alter the base clock frequency in 1MHz increments. The base clock frequencies are currently 100/125/166MHz on Devil’s Canyon. However, Skylake scraps the ratio-based system entirely, allowing higher overall overclocks for those willing to eke out every millimetre of power from their otherwise beastly new CPU.It’s important to note, however, that you’ll need to adjust the core ratio to coincide with what target clockspeed you’re attempting to achieve. For example, if you change the base clock to 300MHz and leave the core ratio at default, you’ll end up trying to achieve a 12GHz overclock. Which, we think, is theoretically impossible at this point in time.So, what does Skylake mean to PC enthusiasts like us? Well, probably that it’s finally time for an upgrade, for starters. Intel is still top dog when it comes to single and multi-threaded processor performance, and this looks unlikely to change any time soon.Hopefully, AMD will bring back some competition via the Zen cores, but who knows how far off that will be. What these K-series processors have shown us, however, is that Intel’s famously weak integrated graphical horsepower has been increased considerably compared to the last series. And, although those running the overclockable chips are hardly likely to be utilising integrated graphics alone, this does give us a good insight into the capability of the more mainstream chips being released later this year, which is especially interesting for those running laptops and other Intel-powered mobile devices.As much as Skylake is still an incredibly competitive chip, however, it still doesn’t hold pace with Haswell-E. The extreme edition processors benefit hugely from the additional cores, and no amount of Hyper-threading or core performance will beat that for the time being. What we did find during our testing of Skylake was that if you overclocked the CPU up to 5GHz, it actually matched benchmark performance with that of the entry level model i7-5820K at stock. For an enthusiast-grade chip, that’s one hell of an achievement.Over the next few years, we’ll no doubt see some incredible advancements when it comes to computational power. If Intel keeps this progress up, 10nm processors might not be as far away as many may think. And with 3D Xpoint landing sometime next year, the next phase may change how we look at the world entirely. It’s an exciting time to be a tech enthusiast, that’s for sure.