Introduction, 8th Generation Platform Chipset
To say 2017 has been a busy year for desktop-PC processors would be an understatement the size of Texas—or at least, Oregon. The best way to sum it all up might be to say, simply: In 2017, you’ll get more cores (and more threads) for your CPU dollar than ever. That keeps getting reaffirmed as the year goes on—and it’s not over yet.
AMD kicked off the trend with its eight-core Ryzen 7 chips in March, topping out on that platform with the Ryzen 7 1800XRyzen 5 1600XAMD Ryzen 3 1300XCore i9-7980XE Extreme Edtion. That $1,999 mega-chip made AMD’s competing counterpart, the 16-core Ryzen Threadripper 1950XIntel’s 8th Generation Core U-Series mobile chips. Those were just starting to trickle out into slim laptops and convertibles when we wrote this, promising quad-core performance in systems that previously had been offered only with dual-core silicon. For a deeper discussion of 2017’s developments in desktop consumer processors, please see our recent reviews of the Intel Core i9-7900XAMD Ryzen Threadripper 1920XComponent Reviews summary/listing page and sample the 19 desktop processor reviews we’ve written this year, starting with the Intel Core i7-7700K, the predecessor to the subject of our review today. We’ll wait.
Now that you’re back and thoroughly caught up, it’s time to take a look at the first of Intel’s 8th Generation Core desktop processors, the family code-named “Coffee Lake.” Much like the company’s first 8th Generation mobile chips, the Core i7-8700K that we’re looking at here, as well as the Core i5-8400 that we tested and reviewed in tandem with the new Core i7, are essentially built on the same architecture as the 7th Generation Core “Kaby Lake” processors (which were, in turn, very similar to the 6th Generation Core “Skylake” chips, like that family’s head, the Core i7-6700K). Aside from some additional hardware that supports copy-protected 4K streaming for services like Netflix (which came in with the Kaby Lake chips), the basic architecture across these three generations is nearly the same, by Intel’s own admission.
To be clearer about that aspect, the new 8th Generation chips are once again built around a 14-nanometer (nm) manufacturing process, though Intel dubs the process used with its latest chips “14nm++.” Chips such as the Core i7-6700K (6th Generation/Skylake) were the company’s initial 14nm parts, while CPUs like the Core i7-7700K (7th Generation/Kaby Lake) are built on a 14nm+ process. So hence, with this third iteration of the 14nm process, we arrive at 14nm++.
There are no 10nm chips to be found here, but because of this further refinement of Intel’s manufacturing process, Intel has been able to crank up its top clock speeds as high as 4.7GHz for the Core i7-8700K that we’re looking at here. To stick within the 95-watt thermal envelope, though, Intel has dropped the base clock of this chip to 3.7GHz, versus the 4GHz base of the previous-generation Core i7-7700K.
The real advancement, though, comes in the number of cores (and following from that, the maximum possible processing threads), in keeping with 2017’s CPU theme. While Intel’s previous-generation mainstream consumer processors topped out with four cores and eight computing threads in the past, the Core i7-8700K has six cores and 12 threads. And the Core i5-8400 has six cores and six threads. (It lacks Intel’s thread-doubling Hyper-Threading technology that lets a core handle two processing threads at once.) That means, in theory at least, that these new chips are capable of up to a 50 percent performance boost in tasks that are able to take advantage of all available cores. And single-threaded performance (where Intel has long held a healthy lead) should be higher as well, thanks to higher top boost-clock speeds on these chips.
But can the six-core Core i7-8700K deliver the goods against similarly-priced AMD Ryzen 7 chips that have eight cores and 16 threads? And does Intel’s new on-chip integrated graphics solution, dubbed Intel UHD Graphics 630, also provide a significant speed boost versus the previous generation integrated graphics processor (IGP)? To find out, of course, we’ll have to delve deep into our benchmark testing. But first, we’ll take a look at the 8th Generation Core platform as a whole, which includes six new chips at this stage, plus the new Z370 chipset.
“New chipset”: Yes, that means you’ll need a new motherboard to take advantage of Intel’s Coffee Lake desktop processors. Are Intel’s new chips worth a pricey, complicated upgrade? And what about gaming performance with a dedicated graphics card? We’ll endeavor to answer all those questions and more below.
Ryzen 5 1600X was one of our favorites in the whole Ryzen lineup.) The Ryzen 5 CPUs compete with Intel’s four-core (four-thread) Core i5 chips like the Core i5-7600K.
Clearly, Intel was going to have to offer up a response to AMD’s higher-core-count Ryzen chips at some point, and these Coffee Lake chips are arguably the first salvo. Specifically, we’re looking at the six-core, 12-thread Core i7-8700K here, although we’ve also tested the six-core, six-thread Core i5-8400 at the same time. But these aren’t the only new chips Intel is rolling out in this update. There are six chips in total in the new 8th Generation Core family (for now). Here’s a summary of their specs, direct from Intel…
There’s plenty to take in from the image above. For starters, the Core i7-8700K we’re focusing on here is priced at about $20 more than what was the launch price of the Core i7-7700K that it’s replacing. While it’s never a great thing to see pricing creep up from one generation to the next, we don’t think the bump is significant or unjustified here given the 50 percent increase in cores. Anyone prepared to spend more than $300 on a processor in the first place, and keen on maximum core/thread count, can find a way to cough up the extra Jackson.
Arguably more interesting is the chip’s TDP (thermal design power, a measurement of heat-dissipation requirements), which Intel rates at 95 watts. That’s just 4 watts higher than the four-core Core i7-7700K, despite the two additional cores. Given (as we noted above) that the architecture with these 8th Generation Core chips is effectively the same as what’s found in 7th Generation chips, Intel had to do some kind of jiggery-pokery to keep the Core i7-8700K from running significantly hotter than its predecessor.
Most of that seems to have happened with clock speeds. The Core i7-8700K’s top Turbo Boost speed (4.7GHz) is 200MHz higher than the 4.5GHz ceiling of the Core i7-7700K. But the new chip’s base clock of 3.7GHz is 300MHz lower than the 4GHz base clock of the older CPU. We’ll have wait for benchmarks to see how that translates to performance, but we’ll say here that the lower base clock didn’t seem to cause any negative performance issues other than, perhaps, a bit more variance, run-to-run, in our benchmark tests than previous chips.
Other additions with these new chips include more total cache (pretty much expected, given the extra cores throughout the lineup), and a bump up in officially supported RAM speeds (to 2,666MHz, with the Core i5 and i7 chips). Note, though, that Intel has long been conservative with its rated RAM support. Memory makers have offered kits with higher-than-spec RAM speeds for years. Indeed, the G.Skill Trident Z memory we used for our testing is rated to 3,600MHz, and it ran at that setting just fine during our testing.
8th Generation Platform Z370 Chipset
As for the platform as a whole, there’s not a whole lot (or much at all, really) that’s new, beyond the new chips and a new chipset. Here’s how Intel laid out the details in its press materials…
To be clear, the 8th Generation Core chips drop into the same LGA 1151 socket that was used for 6th and 7th Generation chips. But though the socket is shaped the same as before (and is compatible with the same cooling solutions), Intel says you’ll need a new Z370-chipset-based motherboard to use one of the new 8th Generation chips. And you can’t put one of the older Skylake or Kaby Lake chips in the new motherboards, either.
The reason, according to Intel, is that the company had to beef up its power-delivery circuitry for the additional cores in the new chips. While there may well be electrical and thermal reasons that necessitate new motherboards, it’s no consolation for those who recently bought a now previous-generation Z270 motherboard and would like to upgrade to one of these new chips. Given that Z270 just officially launched alongside the Core i7-7700K in January of 2017, the life cycle of the 7th Generation desktop chips and their accompanying platform seems cruelly short. Not that older chips and boards will be disappearing overnight, but desktop platforms and their accompanying chipsets/motherboards usually have a longer shelf life than just nine months before being relegated to last-generation status. No doubt, plenty of consumers who bought a new Z270 motherboard this past spring or summer will be unhappy to learn how their new board suddenly becomes a dead-end platform in the same year.
But what of the new Z370 chipset, then? Does it offer up substantive new features versus the Z270 it’s replacing after less than a year? The short answer: no. Here’s how Intel describes Z370 in its press materials surrounding the 8th Generation processor launch…
While the key board makers such as Asus, Gigabyte, and MSI, no doubt, will find new features to add to their Z370 motherboards, the new stuff that Intel brings to the table with the chipset is pretty much down to improved power delivery for those extra cores and overclocking, as well as official support for faster memory. And remember that, for enthusiasts and gamers, that memory-speed boost is effectively meaningless, as RAM that runs at faster speeds has been available for a long time.
So, we have six new chips, which are a whole lot like the previous-generation parts, just with more cores and slightly higher clocks, and a new platform that’s also very similar to what came before it, just with extra circuitry to handle the power demands of those extra cores. What about the IGP on these chips, for those who don’t care much about gaming? Well, for starters, it’s important to remember that AMD’s Ryzen chips don’t have any integrated graphics at all, necessitating the use of a dedicated graphics card. For those who don’t care much about gaming, that pushes things in Intel’s favor, because you don’t have to buy a graphics card with Team Blue’s CPUs if you don’t want to. And unless you have an older graphics card that you can carry over, even a low-end current-gen graphics card from AMD or Nvidia will set you back at least $70 these days.
As for the integrated UHD Graphics 630 found on the 8th Generation Core chips, Intel told us the underlying silicon is basically the same as last generation’s HD Graphics 630, though users should see some improved performance thanks to a slightly higher ceiling on the IGP’s clock (what Intel calls the “Graphics Max Dynamic Frequency”). But looking at the numbers, that spec for the UHD Graphics 630 on the Core i7-8700K has jumped by only 50MHz, from 1.15GHz on the Core i7-7700K, to 1.2GHz on the new six-core chip. So expect only modest gains in frame rates on that front, as we’ll see later in testing. But a more dramatic bump in frame rates does come when you pair this chip with a dedicated graphics card and set your resolution to 1080p. When paired with an Nvidia GeForce GTX 1080, this chip delivered higher frame rates at 1080p than any other chip we’ve tested to date.
First, though, on to the CPU tests to see what six cutting-edge Intel cores can do against eight from AMD.