Re­views & Rat­ings

In­tel’s com­bi­na­tion of Core i7 and Radeon RX Vega ex­ceeds per­for­mance ex­pec­ta­tions and rep­re­sents a fu­ture threat to Nvidia.

PCWorld (USA) - - Contents - BY GOR­DON MAH UNG

Kaby Lake G’s mar­riage of In­tel CPU and AMD GPU is an un­usual part­ner­ship in the spirit of peanut but­ter and choco­late, R2-D2 and C3PO in Star Wars, and, yes, even Tom Hanks and the dog in Turner and Hooch. Peo­ple love the un­ex­pected.

Built out of an In­tel 8th-gen­er­a­tion quad­core CPU and an AMD cus­tom Radeon RX Vega M ( go.pc­world.com/rvgm) graph­ics chips, Kaby Lake G shook the PC in­dus­try when In­tel an­nounced the chip at CES ( go. pc­world.com/5prc). Af­ter putting Kaby Lake G through the wringer via HP’S Spec­tre x360

15 ( go.pc­world.com/ hp15), it’s now clear to us that this new CPU/ GPU com­bi­na­tion may very well rep­re­sent the fu­ture of the PC and de­serves the fear it’s gen­er­at­ing ( go.pc­world. com/nvpp) among com­peti­tors.

WHAT IS KABY LAKE G?

When Kaby Lake G was first an­nounced, many as­sumed In­tel had con­tracted with AMD to re­place its own graph­ics cores on the CPU die. In fact, the module houses an In­tel CPU with In­tel in­te­grated graph­ics along with an AMD Radeon RX Vega M GL graph­ics chip and mem­ory.

Rather than con­nect the chips us­ing tra­di­tional meth­ods, Kaby Lake G does it all with In­tel’s Em­bed­ded Multi-die In­ter­con­nect Bridge (EMIB). In­tel says its EMIB costs far less than com­pet­ing tech­niques for con­nect­ing mul­ti­ple dies and is far eas­ier to im­ple­ment as well.

On Kaby Lake G, a con­ven­tional x8 PCIE 3.0 con­nec­tion joins the CPU to the GPU. In­tel uses its EMIB to con­nect the cus­tom Radeon graph­ics core with 4GB of HBM2 mem­ory. The re­sult­ing module is a whole lot smaller and thin­ner than a tra­di­tional setup. Kaby Lake G also of­fers more fine-grain power con­trol of the com­po­nents. With a tra­di­tional sep­a­rate CPU and GPU, one part doesn’t know what the other is do­ing. It’s re­ally up to the lap­top maker to man­age it all.

With Kaby Lake G, the power and ther­mal needs of the CPU, GPU, and the RAM for the

GPU are all man­aged as one. If the module’s un­der a heavy graph­ics load, the CPU can back off. If the CPU is un­der a heavy load, the GPU can back off. That ini­tially led many to as­sume that Kaby Lake G was paired with a lower power 15-watt “U” se­ries chip. Kaby Lake G is in­stead based on an “H” part, which is rated at 45 watts and can run at 56 watts un­til it heats up.

IS IT PO­LARIS OR VEGA? IT PROB­A­BLY DOESN’T MAT­TER

We re­ported ( go.pc­world.com/lkgm) ear­lier this year that although In­tel branded Kaby Lake G with AMD’S new­est and best graph­ics “Vega” brand, it ap­pears to be based on AMD’S older stock of Po­laris graph­ics cores used in the RX 580 se­ries. In­tel just spiced up Po­laris with Vega el­e­ments, in­clud­ing high­band­width cache and HBM2 mem­ory. In­tel of­fi­cials de­clined to com­ment.

So did In­tel lie? Did it mis­rep­re­sent some­thing as Vega that’s ac­tu­ally Po­laris? No. Brand­ing is ar­ti­fi­cial. In­tel could, for ex­am­ple, in­tro­duce a new Atom-based CPU and call it a Core i9 if it wanted to. (Yes, the fall­out would be hor­rific, but that’d be on them.) In the end, it’s a cus­tom GPU with a lot of ad­vanced fea­tures.

KABY LAKE G GAM­ING PER­FOR­MANCE

Is In­tel’s Kaby Lake G good enough for gam­ing? The short an­swer is yes. In­tel has said Kaby Lake G will com­fort­ably com­pete

with a Ge­force GTX 1050 in gam­ing per­for­mance, and for the most part we find that to be true.

The longer an­swer is: It de­pends. As with all things, cer­tain games and even cer­tain parts of games will fa­vor var­i­ous fea­tures of a GPU, such as mem­ory band­width or shader per­for­mance, as well as the ac­tual ar­chi­tec­ture of the chip. In gen­eral, though, we’d say that the Radeon

RX Vega M GL com­pares well to a GTX 1050 in per­for­mance.

Our first test is

Fu­ture­mark’s 3Dmark Sky

Diver. It’s a pop­u­lar, ba­sic syn­thetic graph­ics test. As you can see, when com­pared to other GTX

1050 lap­tops as well as ma­chines in its class, it does very well.

Go­ing up against more typ­i­cal work­horse lap­tops isn’t quite as fun as see­ing how the Core i7-8705g stacks up against gam­ing lap­tops, so we ran a few games on the Spec­tre x360 15 as well. The first is the ven­er­a­ble Tomb Raider at 1080p res­o­lu­tion and set to the Ul­ti­mate pre­set.

We’ve found the circa-2013 Tomb Raider, like many older games, can be par­tic­u­larly sen­si­tive to CPU per­for­mance. The re­sults here speak well for the Core i7-8705g Kaby

Lake: It eas­ily out­paces a Core I5-7300HQ with GTX 1050 Ti and a Core I7-7700HQ with GTX 1050 GPU.

Mid­dle-earth: Shad­ows of Mor­dor also agrees that the Radeon RX Vega M GL in the Kaby Lake G is a pretty de­cent chip. Mid­dleearth also tells us it ain’t no Ge­force GTX 1060.

Although Kaby Lake G does well in Tomb

Raider and Sky Diver, the re­al­ity of mod­ern gam­ing is that some­times it may not beat the com­pe­ti­tion. In fact, in Rise of the Tomb Raider, it’s ac­tu­ally slightly slower than a Ge­force

GTX 1050.

We could run through a few more gam­ing bench­marks, but you get the gist: It stacks up nicely against the Ge­force GTX 1050 in most games.

Let’s turn back to 3Dmark Sky Diver, where we tal­lied up pure graph­ics scores from var­i­ous lap­tops that are ac­tu­ally “por­ta­ble.” By por­ta­ble, we mean lap­tops that are around five pounds, not beefy six- and eight-pound mon­sters. Porta­bil­ity lim­its you to a max­i­mum of a Ge­force GTX 1080 Max-q lap­top.

Clearly, when you’re look­ing at a

GTX 1080 Max-q or

GTX 1070 Max-q lap­top, it’s a ton more per­for­mance. But those de­signs come with weight and bat­tery costs. When you look at Kaby Lake

G in the con­text of por­ta­ble lap­tops, it does quite well.

On our chart (to the right), we also high­lighted three pre­vi­ous HP Spec­tre x360 15 lap­tops. If we as­sume that HP used the most pow­er­ful parts avail­able at the time for the chas­sis, we’ve gone from In­tel in­te­grated graph­ics to

Ge­force 940MX to

Ge­force MX150 to

Radeon MX Vega

M GL.

From the graph­ics per­for­mance side of things, that’s pretty re­spectable. Sure, it’s not Ge­force GTX 1060 by any stretch of imag­i­na­tion, but it’s still an im­pres­sive chip.

KABY LAKE G CPU PER­FOR­MANCE

As im­por­tant as graph­ics per­for­mance is, we also want to as­sess the Core i7-8705g as a

CPU. For that we broke out a few that we think it should com­pare well to, start­ing with the ubiq­ui­tous Core I7-7700HQ in the orig­i­nal Asus ROG Ze­phyrus lap­top ( go. pc­world.com/zphy).

We also wanted to see how a higher-end chip would per­form so we ran a few tests on a Len­ovo Le­gion Y920 with its Core I7-7820HK in de­fault stock mode (which was pretty con­ser­va­tive) and in its man­ual “turbo mode.” The Le­gion has a base de­fault set­ting and an over­clocked set­ting, which we also tested on.

The last chip is the one that’s sim­ply not fair, but it would be wrong to not in­clude: the new 8th-gen 6-core Core i7-8750h in an MSI GS65 Stealth Thin ( go.pc­world.com/gs65).

One big caveat: Un­like re­views of desk­top CPUS, a re­view of a lap­top CPU isn’t just the Cpu—it’s re­ally the en­tire plat­form be­ing judged. With a lap­top you have no con­trol over the cool­ing, the moth­er­board, or any of the other com­po­nents.

Mak­ing this even more dif­fi­cult is what each lap­top maker de­cides to tune for.

More noise? Less heat?

More per­for­mance? Any of th­ese can im­pact CPU per­for­mance greatly. Ideally, you’d want to be able to use the same plat­form for all of the tests, but that’s just not pos­si­ble right now.

Still, that doesn’t mean com­par­isons are worth­less.

For the Core I7-7700HQ per­for­mance, for ex­am­ple, we made sure to do spot checks of the ROG Ze­phyrus against other Core

I7-7700HQ re­sults we’ve seen. For the most part, it’s right where that par­tic­u­lar

Kaby Lake CPU should be.

CINEBENCH R15 PER­FOR­MANCE

Our first test is Cinebench R15. This 3D ren­der­ing test is al­most en­tirely a CPU test and loves threads and clock speed.

Although the 6-core leads the way by a yuge mar­gin, you have to re­spect the

numbers of the Kaby Lake G Core i7-8705g as it out­per­forms both 7th-gen CPUS. The rea­son for this is sim­ple: We’ve no­ticed In­tel and ven­dors are far more com­fort­able push­ing 8th-gen chips to higher clock speeds than the 7th gen­er­a­tion.

The world isn’t about multi-threaded code, though, so we also run Cinebench us­ing a sin­gle thread to sim­u­late how the CPUS would per­form in the vast ma­jor­ity of ap­pli­ca­tions.

When mea­sur­ing sin­gle-threaded per­for­mance, the num­ber of cores no longer mat­ters, so we see the 6-core Core i7-8750h come back down to earth. Just as we saw with multi-threaded loads, both 8th-gen CPUS have a sig­nif­i­cant clock speed ad­van­tage. The Core i7-8750h is on top, but nip­ping at its heels is the Core i7-8705g. Sur­pris­ingly, the Core I7-7820HK, even in its man­ual over­clock mode, is run­ning at lower clock speeds than the 8thgen parts.

One weak­ness of Cinebench R15 is that it takes only a minute to run on fast CPUS. To see what hap­pens to the CPU af­ter a lap­top heats up we turn to Hand­brake, where we con­vert a 30GB 1080p file us­ing the An­droid pre­set. This can take any­where from a cou­ple of hours on a dual-core CPU to 45 min­utes on a quad­core CPU.

What we typ­i­cally see on Core i7 CPUS is much flat­ter per­for­mance, once the high clock speed ad­van­tage it has burns off. While most Core i7 CPUS might run at 3.9GHZ for a minute or three, they will usu­ally per­form 90 per­cent of the work at 3.6GHZ or 3.5GHZ.

The 6-core Core i7-8750h eas­ily wins this thanks to its two ad­di­tional cores. On the Core i7-8705g Kaby Lake G, we see it nearly dead-even with the Core I7-7700HQ CPU. Oddly, the per­for­mance of the Le­gion Y920 on de­fault speed is pretty se­date. Push the turbo slider, though, and it’s off to the races.

It’s not just Hand­brake and Cinebench that agree. We also ran the set of lap­tops through the Chaos Group’s V-ray bench­mark. It’s

an­other multi-threaded bench­mark that can run on the CPU or GPU. For this test, we chose the CPU test. The re­sult again sees the 8th-gen Kaby Lake G ahead of the 7th-gen CPUS ex­cept when the Core I7-7820HK is over­clocked. And yes, Core i7-8750h, you can stop show­ing off. We get it: 6 cores > 4 cores.

Next is Ver­acrypt AES En­cryp­tion bench­mark. The Core I7-7820HK fi­nally squeaks out ahead on its de­fault set­ting, but let’s just call this a tie all the way around (yes, ex­cept for you, 6-core Core i7), and a pretty good show­ing for a con­vert­ible lap­top with Kaby Lake G in­side.

Let’s cap this off with our fi­nal test (op­po­site top), where we take Cinebench R15 and mea­sure per­for­mance with the thread load man­u­ally set from one to eight. It’s no sur­prise that the Core i7-8705g is ahead un­der all loads over a 7th-gen Core I7-7700HQ.

One prob­lem with the fol­low­ing chart) is that it doesn’t ac­tu­ally show the per­cent in­crease, which might lead you to think the Core i7-8705g’s CPU per­for­mance edge is on the far right. The ac­tual per­for­mance edge of the Kaby Lake G is on the far left.

TL;DR: IT’S ALL CLOCK SPEED

It’s no sur­prise that the

7th-gen CPUS aren’t that much dif­fer­ent from the 8th-gen chips. What’s dif­fer­ent is the clock speeds they run at. In­tel has been us­ing the 14nm process for so long now, it’s com­fort­able push­ing far higher clock speeds. To get a feel for how much higher, we again took Cinebench and logged the clock speed of the CPU when it was 20 sec­onds into the test. This par­tic­u­lar chart has the scal­ing set for read­abil­ity, but you’re ba­si­cally look­ing at a 200MHZ across­the-board per­for­mance ad­van­tage.

WHAT ABOUT THER­MAL LIM­I­TA­TIONS?

You know Kaby Lake G uses Dy­namic Power Shar­ing to help goose the CPU per­for­mance to top speeds, but you’re prob­a­bly won­der­ing how much of a lim­i­ta­tion that is

when there’s a GPU load, too. To find out, we ran the graph­i­cally in­tense Fur­mark stress test on the Spec­tre x360 15. We then ran Cinebench R15 and saw a pretty steep de­cline in its score. We don’t want to put a firm num­ber on the per­for­mance be­cause it never sta­bi­lized. That’s a bad thing, right?

That’s what we ini­tially thought, un­til we ran the same load on an older Dell XPS 15 9560 with a Core I7-7700HQ and Ge­force GTX 1050. In ac­tual per­for­mance, both are some­what sim­i­lar when the CPU and GPU are tested alone. In a stress test of both, we ac­tu­ally saw the Core i7-8705g and Radeon RX Vega M GL man­age its ther­mals far bet­ter than the Core I7-7700HQ and Ge­force GTX 1050 com­bi­na­tion. In fact, once it was heated up, the XPS 15 with tra­di­tional CPU+GPU per­formed far worse.

While this won’t ap­ply to all Kaby Lake G lap­tops, it’s def­i­nitely a sign that we can’t as­sume the com­bined pack­age will un­der­per­form a tra­di­tional Cpu+dis­crete graph­ics setup, be­cause in some cases, it’s faster.

VER­DICT

Over­all, we’re pleas­antly sur­prised by Kaby Lake G. We ex­pected CPU per­for­mance closer to a low-wattage CPU, and GPU per­for­mance be­low a GTX 1050. In­stead, we saw bet­ter per­for­mance than a 7th-gen Core i7 high-wattage chip, and GPU per­for­mance more on a par with a GTX 1050.

Re­mem­ber, too, that the Spec­tre x360 15 is a 2-in-1 that con­verts to a tablet. We’ve seen a few 15-inch con­vert­ibles with high-power parts in them, and they gen­er­ally un­der­per­form tra­di­tional clamshell de­signs. With Kaby Lake G, you can ap­par­ently have your cake and still fold it back into a tablet, too.

HERE’S WHY NVIDIA (AND AMD) SHOULD BE SCARED OF KABY LAKE G

As good as it is, Kaby Lake G isn’t go­ing to shake up the Cpu+ge­force scene to­day. But to­mor­row, if there’s a Can­non Lake G or a Whiskey Lake G with more cores and bet­ter graph­ics, AMD and Nvidia should be wor­ried.

What’s bad for Nvidia is how the in­te­grat­edCPU-AND-GPU de­sign con­cen­trates power with In­tel. If In­tel buys the graph­ics chip and adds it, the lap­top ven­dor is no longer mak­ing the choice, po­ten­tially freez­ing out Nvidia.

AMD isn’t sit­ting pretty ei­ther. To­day In­tel is buy­ing Radeon graph­ics, but the com­pany re­cently an­nounced its in­tent to make its own dis­crete graph­ics ( go.pc­world.com/2020). It’s en­tirely pos­si­ble a fu­ture “G” chip will fea­ture In­tel dis­crete graph­ics, not AMD’S.

To­day though, there are few tak­ers of Kaby Lake G. In fact, only two ven­dors have shipped it: HP, with the Spec­tre x360 15, and Dell, with its XPS 15 2-in-1. Some we’ve spo­ken to have painted that as a fail­ure of Kaby Lake G to catch on, while oth­ers have spec­u­lated pol­i­tics to be the cause. What­ever the truth, it’s a shame, be­cause ap­plied the right way in the right lap­top, Kaby Lake G is a road worth tak­ing.

In­tel’s new EMIB is used only to con­nect the HBM2 mem­ory with the cus­tom Radeon graph­ics.

On the right is a CPU, GPU, and HBM2 graph­ics mem­ory pack­age in Kaby Lake G. On the left is a tra­di­tional CPU, GPU, and GDDR5 graph­ics assem­bly.

Like Darth and Luke work­ing to­gether to bring or­der to the gal­axy, Kaby Lake G al­lows for far con­trol .

In some game loads, the Radeon RX Vega M GL punches well out of its class.

With its CPU per­for­mance and the Radeon RX Vega M GL, the Spec­tre x360 15 has a slight edge over GTX 1050 lap­tops

On a longer work­load, the Kaby Lake G’s high clock speed ad­van­tage starts to evap­o­rate putting it closer to a Core I7-7700HQ CPU in per­for­mance.

The Core i78705G in a con­vert­ible lap­top out­paces a Core I7-7700HQ in a gam­ing lap­top.

The per­for­mance ad­van­tage the Core i7-8705g Kaby Lake G has is more ap­par­ent on light loads.

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