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 C-3PO 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 quad-core CPU and an AMD custom Radeon RX Vega M graphics chips, Kaby Lake G shook the PC industry when Intel announced the chip at CES. After putting Kaby Lake G through the wringer via HP’s Spectre x360 15, 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 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 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 high-bandwidth 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. Middle-earth 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 below, 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.
Keep reading for Kaby Lake G CPU performance benchmarks.