Core i7-8700k: In­tel’s re­sponse to Ryzen is faster and cheaper than ever

In­tel’s aptly named Cof­fee Lake of­fers a fre­netic amount of per­for­mance at prices un­heard of from the chip gi­ant.

PCWorld (USA) - - Reviews Google Pixel 2 Xl - BY GOR­DON MAH UNG

In­tel’s 6-core 8th gen­er­a­tion Core i7-8700k CPU is the re­al­ity check to high-per­for­mance, high-priced CPUS like the $2,000 Core i9 ( go.pc­world. com/2ci9) and $1,000 AMD Ryzen Thread­rip­per ( go.pc­ The real bat­tle for the desk­top and con­sumer’s wal­lets is with this amaz­ingly af­ford­able (for In­tel any­way) $359 CPU ( go.pc­world. com/35cp), code-named Cof­fee Lake.

In fact, the Core i7-8700k is In­tel’s first real re­sponse to AMD’S break­through se­ries of Ryzen 5 ( go.pc­ and Ryzen 7 CPUS ( go.pc­, and a vi­able

al­ter­na­tive to the Zen-based CPUS. But just how fast is it, and which CPU should you buy? Read on to find out.


Moore’s Law isn’t dead, but the abil­ity to shrink CPU cir­cuits and in­crease den­sity has dras­ti­cally slowed down. Cof­fee Lake, for ex­am­ple, is based on the same 14nm process the com­pany in­tro­duced with its Broad­well line of lap­tops CPUS in 2014. Since then, In­tel has used the 14nm process on Sky­lake, Kaby Lake, and now Cof­fee Lake. De­spite the sim­i­lar process, how­ever, In­tel says it’s made enough im­prove­ments along the way to call Cof­fee Lake a “14nm plus plus” chip. A sim­pler way is to think of Cof­fee Lake as an im­proved 7th-gen­er­a­tion Kaby Lake chip with two more cores, though there are some sub­tler changes.

So yes, cyn­ics, the only true “8th-gen­er­a­tional” part may be the name it­self. Folks of a more for­giv­ing mind­set will see 8th-gen chips as a big break­through for

In­tel, which has of­fered quad-core CPUS as lux­ury models exclusively for the last ten years. Con­sider that In­tel once charged $1,000 for 6-core CPUS. With Cof­fee Lake, you’re get­ting two more cores for the nearly the same price as Kaby Lake and Sky­lake.


Although Cof­fee Lake is es­sen­tially an im­proved Kaby Lake CPU, some key changes will drive In­tel fans sim­ply batty. The main one is its in­com­pat­i­bil­ity with older moth­er­boards, de­spite us­ing the ex­act same phys­i­cal LGA1151 socket.

Why, In­tel, why? The com­pany cites sev­eral changes. The first is of­fi­cial sup­port for DDR4/2666 in­stead of of DDR4/2400. The higher-clocked RAM re­quired more tightly con­trolled lay­out of the wires or “traces” on the motherboard, which man­dated new de­signs.

Cof­fee Lake also adopts the nifty “per core” over­clock­ing first in­tro­duced with the Core i7-6950x Broad­well-e. This al­lows a user to over­clock just in­di­vid­ual cores based on the work­load.

All this added up to the Z370 chipset you’ll find on new moth­er­boards, the com­pany said. One thing that isn’t clear, how­ever, is why Z370 won’t work with older CPUS. Be­cause both the Z270 and Z370 use the same socket and pretty much the same chipset pinout, why can’t you put your older 7th-gen Kaby Lake into a newer Cof­fee Lake

Z370 mobo? All In­tel would say is its board part­ners ac­tu­ally re­quested a clean break from the past with the new chipset.


For this re­view, we looked at the top chip of the lineup: the Core i7-8700k. We com­pared it pri­mar­ily to its neme­sis: AMD’S Ryzen 7 1700X. Although technically priced at $399, we eas­ily found the chip for $359 at Amazon. com ( go.pc­ or even cheaper when on sale.

Our orig­i­nal re­view of the Ryzen 7 ( go. pc­ was fo­cused on the top CPU, the Ryzen 7 1800X, but a lot has changed since March. So we took our orig­i­nal Asus Crosshair VI Hero build, up­dated to the lat­est avail­able BIOS, in­stalled a fresh copy of Win­dows 10, and the lat­est AMD driv­ers and Ryzen power plan.

We also changed out the RAM. Our orig­i­nal Ryzen test filled all slots with DDR4 RAM, which lim­ited the mem­ory speed to JEDEC stan­dard DDR4/2133 (a limitation of Ryzen at the time). For the Cof­fee Lake show­down, we dropped in 16GB of DDR4/3200 in­stead, to give the Ryzen 7 chip ev­ery op­por­tu­nity to shine. If you don’t fol­low cur­rent events, you should know Ryzen’s mem­ory con­troller and In­fin­ity Fab­ric have a very close re­la­tion­ship, and the high­er­clocked the mem­ory you use, the higher the per­for­mance po­ten­tial.

For GPU we again used a Founders Edi­tion Geforce GTX 1080 card, up­dated with the lat­est Nvidia driv­ers.

On the In­tel side, we used a Gi­ga­byte Aorus Gam­ing 7 board with a match­ing Founders Edi­tion Geforce GTX 1080 card, a clean in­stall of Win­dows 10, and the same model of Kingston SATA SSD for the pri­mary boot drive.

For RAM, we ini­tially used a match­ing set of 16GB DDR4/3200 from our Ryzen build.

When cal­i­brat­ing our sys­tem against num­bers pro­vided by In­tel, we found the sys­tem ac­tu­ally per­formed slower when select­ing the XMP pro­file for 3,200MHZ. In the end, we swapped in an­other pair of mod­ules rated at 2,400MHZ and got closer to the num­bers In­tel said we should ex­pect.


To dig into the per­for­mance char­ac­ter­is­tics of Core i7-8700k, we ran the CPU through a gaunt­let of ren­der­ing, en­cod­ing, and other pro­duc­tiv­ity tests. If you use mostly Of­fice ap­pli­ca­tions, a browser and gam­ing, our sin­gle-threaded per­for­mance re­sults mat­ter more. If you edit video or per­form other Cpu-in­ten­sive tasks on your PC, pay closer at­ten­tion to the multi-hreaded per­for­mance.


Our first test is Maxon’s Cinebench R15. It’s a pop­u­lar, free bench­mark based on the same en­gine used in the com­pany’s pro­fes­sional Cin­ema 4D pro­gram. Pro­fes­sional 3D ren­der­ing tends to like CPU cores and threads, and the de­fault set­ting for Cinebench ex­ploits all avail­able cores.

The mul­ti­threaded re­sults bear this out, as the CPUS we’ve tested sort out based on the thread count. In the crazy range, we have In­tel’s Core i9 chips and AMD’S Thread­rip­per. From there the list sorts out nicely based on the num­ber of cores and whether the CPUS have Sym­met­ric Mul­tithread­ing (SMT), or what In­tel calls Hy­per-thread­ing.

In multi-threaded tests, the new Core i7-8700k (the sec­ond orange bar in the chart above) strad­dles the line be­tween the per­for­mance of a 6-core CPU and an 8-core CPU. In Cinebench, which scales very well with the num­ber of cores, it comes very close to the per­for­mance of an 8-core. The Ryzen 7 1700X eas­ily walks away from the Core i7-8700k, but if you have any doubts as to whether Core i7-8700k is bet­ter left to com­pete with AMD’S

6-core Ryzen 5 chips, the re­sult above should an­swer that.

We also run Cinebench in sin­gle-threaded mode to mea­sure the per­for­mance of a CPU when an app or game only uses one core. For the most part, such a test fa­vors CPUS with higher clock speeds and greater ef­fi­ciency. With Core i7-8700k (see the pink bar be­low), you get that in spades, hearts, clubs, and di­a­monds.

With a boost clock of 4.7GHZ, the Core i7-8700k slides past the pre­vi­ous top dog, the Core i7-7700k which has a top boost clock of 4.5GHZ. In­tel ac­tu­ally dom­i­nates the sin­glethreaded per­for­mance with 8th-gen, Kaby Lake and Sky­lake-x lin­ing up in an or­derly fash­ion ahead of the pack of older In­tel CPUS and

AMD’S chips.

AMD fans will protest that sin­gle-threaded per­for­mance doesn’t mat­ter in a mul­ti­threaded world, but the harsh truth is a huge swath of ap­pli­ca­tions and games don’t ex­ploit more than one CPU core at a time. De­spite tak­ing a back­seat to Ryzen 7 1700X in the multi-thread­ing test, Core i7-8700k wins this one in a big, big way.


Our sec­ond test is an­other 3D ren­der app called Blender. It’s an open-source, free ap­pli­ca­tion that sees heavy use in many in­de­pen­dent movies. Like Cinebench, it fa­vors more cores and more threads, but we’ve found that it doesn’t al­ways scale that well with core count.

Blender’s per­for­mance can vary greatly with the work­load thrown at it. For our test, we use the free BMW CPU test. The re­sult shows the sheer strength of this spunky lit­tle 6-core Cof­fee Lake chip, which isn’t con­tent to slum it with the 6-core Ryzen 5 and Core i7 Broad­well-e chip. Its score, in fact, is dead even with the 8-core Ryzen 7 1700X. A 6-core chip that can hang with the 8-core chips is some­thing to be re­spected.


The Per­sis­tence of Vi­sion Ray­tracer (POV-RAY,

go.pc­ is a ray tracer that dates back to the days of the Com­modore Amiga. Like Blender and Cinebench, it gen­er­ally fa­vors ef­fi­cient CPU cores. Once again we see the 6-core Core i7-8700k hang­ing closer to the 8-core CPUS than the 6-core chips us­ing the in­ter­nal bench­mark.

We also run POV-RAY’S in­ter­nal sin­gle-threaded test. No sur­prise, the high-clocked Core i7-8700k (light blue, be­low) and Core i7-7700k (light pink, be­low) are in a dead heat. The lineup re­in­forces In­tel’s lead in sin­glethreaded apps, just as we saw in Cinebench. The first AMD CPU strag­gles in at 9th place. If you’re won­der­ing why the Ryzen 7 1700X ac­tu­ally loses to the cheaper 6-core Ryzen 5 1600X, it’s likely due to the slightly higher clock speeds of the budget 6-core chip.


Our fi­nal 3D ren­der­ing test is fairly new to us and ac­tu­ally came to our at­ten­tion through AMD. Our sam­ple set is smaller, but it again shows the Ryzen 7 1700X just can’t shake the Core i7-8700k (the blue bar at the bot­tom). The Ryzen 7 wins—but by an un­com­fort­ably slim mar­gin con­sid­er­ing it packs four more threads than the Core i7-8700k.


The world isn’t all about ren­der­ing 3D models, of course. More peo­ple are likely to be en­cod­ing video in­stead, which is where the free and pop­u­lar Hand­brake en­coder comes in. For this test, we use an older version and con­vert a 30GB, 1080p MKV file us­ing the An­droid Tablet pre­set. Hand­brake tends to fa­vor CPUS with more cores and threads, and we see that fa­mil­iar pat­tern: Core i7-8700k hang­ing right there with the 8-core CPUS, rather than with the 6-core chips. It’s not enough to out­pace the 8-core Ryzen chips or the the 8-core Broad­well-e, but it’s closer than you’d ex­pect.


Our next video test uses Adobe’s pro­fes­sional Pre­miere Cre­ative Cloud 2017 to encode an ac­tual video project shot by our video crew in 4K on a Sony Al­pha cam­era.

For this test, we keep the video project on a Plex­tor PCIE SSD and write the project to the same de­vice, in or­der to re­move stor­age vari­abil­ity from the test.

We use Pre­miere to encode it us­ing the

Blu-ray pre­set and se­lect the Max­i­mum Ren­der qual­ity op­tion, which ups the im­age qual­ity when changing res­o­lu­tion (which we also do.) We spec­ify that Pre­miere use the CPU for en­cod­ing rather than the GPU.

Some video pro­fes­sion­als will scoff at us­ing much slower CPUS for a video job, but im­age-qual­ity snobs will ar­gue that the best re­sult is achieved us­ing the CPU.

The re­sults again put the 6-core Core i7-8700k in the run­ning with the 8-core chips. But we still hear those video pros tsk-tsk­ing our choice of CPU en­cod­ing, so we also ran our test us­ing the Geforce GTX 1080 for Cuda-based en­cod­ing. Though some be­lieve the CPU makes no dif­fer­ence, it’s clear that core count still mat­ters even on a GPU encode. It’s also clear the Core i7-8700k can hang with those 8-core CPUS.


For our Thread­rip­per and Core i9 tests, we didn’t dwell on gam­ing per­for­mance. Although im­por­tant, those who buy $1,000 and $2,000 CPUS need them for ren­der­ing and en­cod­ing, not gam­ing. When you’re talk­ing about $360 main­stream chips, gam­ing mat­ters a lot more. Be­cause we wanted to use the lat­est Geforce driv­ers on our tests, we also re­stricted our re­sults to the Ryzen 7 1700X and Core i7-8700k, as we don’t have ev­ery sin­gle CPU on record us­ing the new­est GPU driv­ers.


Our first test is Fu­ture­mark’s 3Dmark Time Spy test. Fu­ture­mark knows how to cre­ate

beau­ti­ful test scenes, and Time Spy doesn’t let us down. For this test, we record Time Spy’s CPU score, which ob­vi­ously fo­cuses on the CPU rather than the GPU. Time Spy also fa­vors more cores, good news for AMD, whose 8-core Ryzen 7 1700X lands a nose in front.


The thing is, Time Spy uses Directx 12, and the new API’S abil­ity to use more CPU cores. Many games sadly just don’t care that much about hav­ing an 8-core CPU. For ex­am­ple, we use Mid­dle-earth: Shad­ows of Mordor with the high-res­o­lu­tion tex­ture pack loaded to look at the real-world gam­ing per­for­mance of the two chips. That de­cent lead Ryzen 7 1700X had in Time Spy 1.0 evap­o­rates, putting the Core i7-8700k slightly ahead rather than slightly be­hind when the game is set to Ul­tra.

To get a bet­ter feel for what would hap­pen if the graph­ics card weren’t the limit on per­for­mance, we also ran Shad­ows of Mordor us­ing the High set­ting in­stead of Ul­tra. No sur­prise, the re­sult fa­vors the Core i7-8700k’s higher clock speed and greater ef­fi­ciency and you can see the per­for­mance gap open up a lit­tle more.


We also ran Rise of the Tomb Raider at 1920x1080 res­o­lu­tion on the high­est im­age qual­ity pre­set, in Directx 11 mode rather than Directx 12. The Core i7-8700k just runs away

with it here. If you think this is Directx 11’s fault, we also ran it in Directx 12 mode, which ac­tu­ally pushed the Core i7 even fur­ther ahead.

Mind you, Rise of the Tomb Raider re­cently re­ceived a patch that ac­tu­ally im­proves its per­for­mance on the new Ryzen CPUS. This is likely just the mas­sive clock speed ad­van­tage that puts Core i7 in front.


Like Rise of the Tomb Raider, Tom Clancy’s Rain­bow Six Siege also agrees that the clock speed ad­van­tage Core i7 has over Ryzen 7 puts it in front.

As with most games, though, once you in­crease the im­age qual­ity slider to higher set­tings, it turns into a GPU test. On

Rain­bow Six Siege, for ex­am­ple, Core i7 wins, but it’s pretty even.


The bad news for Ryzen 7 come from Deus Ex: Mankind Divided. This par­tic­u­lar game is one of the few AMD ini­tially iden­ti­fied as run­ning bet­ter on Ryzen. With the

res­o­lu­tion at 1920x1080 and the High pre­set, though, Ryzen 7 just can’t beat that high clock speed. Core i7 runs away with it. The re­al­ity is, most peo­ple with beefy GPUS don’t tend to play at High or Medium set­tings, they pick Ul­tra. Once you do that (and it be­comes more about the GPU), it doesn’t mat­ter that much does it?


Our last test is Star­dock’s Ashes of the Singularity: Es­ca­la­tion. Made by Ox­ide as a show­case for the ca­pa­bil­ity of Directx 12, we ran the game at 1920x1080 us­ing the Crazy pre­set. You might choose this to make it a GPU test, but Ox­ide has coded in a bench­mark to stress the CPU more than the GPU. When we se­lect CPU Fo­cused, Ryzen 7 and its 8 cores come out ahead of the 6 cores in Core i7. Still, this is very much the ex­cep­tion. For the most part, the higher clock speeds of Core i7 will put it well ahead of Ryzen 7 in most games. Enough to care about or to mat­ter? Prob­a­bly not.


Be­fore we close this up, we’ll hit you with two more charts. The first is Cinebench R15, but with the work­load set by hand to run from sin­gle-core to 16-cores. If you look at the re­sults, you can see the strengths of ei­ther $360 CPU. For the most part, Core i7 (orange bars) has the ad­van­tage un­til we get to about 12 threads in Cinebench. That’s no sur­prise as it is a 6-core CPU ver­sus an 8-core CPU.

One thing our chart doesn’t show, be­cause of the scale, is how much of an ad­van­tage the Core i7-8700k has in those lightly threaded tasks. So we crunched the num­bers to find the per­cent dif­fer­ence the Core i7-8700k has over or un­der the Ryzen 7 1700X. The re­sults speak of the ad­van­tage Core i7-8700k has up to about 6 threads. Much of that, we be­lieve, comes from the clock speed ad­van­tage. We also looked at the re­ported clock speeds of the CPU dur­ing these tests and found that while the Ryzen 7 1700X clocked up to 3.9GHZ on sin­gle-threaded most of the time, it was seem­ingly locked in at 3.5GHZ. The Core i7-8700k, on the other hand, would hit 4.7GHZ be­fore slowly set­tling down to 4.5GHZ to 4.3GHZ across the work­loads. That’s just a huge clock speed dis­par­ity, and it shows.


Ul­ti­mately how we judge the Core i7-8700k ($370 on Amazon, go.pc­ comes down to two ar­eas: Per­for­mance

and price.

In per­for­mance, it’s pretty clear Core i7-8700k is an im­pres­sive CPU. With its high clock speeds and ef­fi­cient mi­cro-ar­chi­tec­ture, it punches out of its weight class and can ri­val CPUS with two more cores. That high clock also aids it in the very im­por­tant sin­gle-and lightly-threaded work­loads that the vast ma­jor­ity of con­sumers rely on ev­ery day.

In many ways, the Cof­fee Lake Core i7-8700k goes a long to­ward ad­dress­ing a key weak­ness of In­tel’s pre­vi­ous main­stream stan­dard bearer—the Core i7-7700k.

While fast in sin­gle- and lightly-threaded tasks, the quad-core Kaby Lake would lose to the 8-core Ryzen CPUS in heav­ier-duty tasks. The Core i7-8700k doesn’t quite ace the com­pa­ra­ble AMD CPUS in all heavy-duty work, but it comes un­com­fort­ably close in a lot of them and can even match it in a few.

When In­tel fi­nally re­leased its 18-core Core i9-7980x and 16-core Core i9-7960x ( go.pc­, the com­pany took back the per­for­mance crown from AMD’S Thread­rip­per ( go.pc­ Still, few took In­tel se­ri­ously be­cause the pric­ing on the CPUS was so over-the-top, it was clear In­tel didn’t plan to sell many.

It’s clear with Cof­fee Lake, In­tel re­ally wants to sell them. At $360 list, it com­pares very fa­vor­ably to the AMD Ryzen 7 1700X, which has a list price of $400 but can be had for $300 to $360.

As skep­ti­cal we were ini­tially of how In­tel’s 6-core CPU could go toe-to-toe with AMD’S 8-core chips, the tests show Cof­fee Lake is more com­pet­i­tive than we ex­pected and a lot more af­ford­able than ever be­fore from In­tel.


Pick Core i7-8700k ( go.pc­

over Ryzen 7 1700X if you mostly play games, drive Of­fice and a browser, and don’t in­tend to push only con­tent creation apps. Ba­si­cally, it’s the CPU for most peo­ple who want more per­for­mance but don’t re­ally do video edit­ing all the time.

Pick Ryzen 7 1700X ( go.pc­ r717) over Core i7-8700k if you’re look­ing for a budget con­tent creation ma­chine with­out step­ping up to a Thread­rip­per part. As fast as Core i7-8700k is, most peo­ple who do 3D mod­el­ling will gen­er­ally want more cores, and Ryzen 7 1700X has the ad­van­tage there. That ad­van­tage, how­ever, is a pretty damned tiny in a lot of tests, and some­thing AMD and its fans may lose a lot of sleep over.

Pick Core i7-7700k over Core i7-8700k if you want an im­me­di­ate feel­ing of re­morse. With the same ba­sic list price be­tween the two chips (Cof­fee Lake is $10 more) there’s al­most no rea­son to choose a Core i7-7700k over Core i7-8700k, ever. Core i7-8700k can do ev­ery­thing Kaby Lake can do on light tasks, and then give the 8-core Ryzen chips a hard time, too. The only pos­si­ble rea­son we could see to buy Core i7-7700k is a good price or the motherboard you have just won’t work with Core i7-8700k. But yeah, just don’t.

Here’s the full line up of “8th gen­er­a­tion” CPUS from In­tel.

The Gi­ga­byte Aorus Gam­ing 7 used for our tests fea­tures the ex­act same socket that pre­vi­ous-gen­er­a­tion In­tel chips used but will work only with 8th-gen­er­a­tion chips.

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