Hardware Overview and System Performance
The ZenBook 3 is the first laptop I’ve tested this year that uses an Intel ‘Kaby Lake’ processor. Succeeding Skylake, Kaby Lake is Intel’s third 14nm processor family, and the first to break away from the company’s long-held tick-tock schedule.
While Kaby Lake is a 14nm part, it’s manufactured using an improved (14FF+) process that brings efficiency improvements at the same clock speeds as Skylake. While Kaby Lake has roughly the same IPC as Skylake, all Kaby Lake parts are clocked a few hundred MHz higher than their Skylake counterparts while still fitting into the same power consumption bracket.
The ZenBook 3 is available in two configurations with differing processors, RAM and storage (although these may vary by region):
- $1,099: Core i5-7200U, 8 GB of RAM, 256GB SSD
- $1,599: Core i7-7500U, 16 GB of RAM, 512 GB SSD
Asus provided me with a model that isn’t available in the United States (at least on Amazon), as it packs the faster Core i7-7500U and a 512 GB SSD but just 8 GB of RAM. I’d prefer 16 GB of RAM for heavy professional workloads, but for the most part I didn’t run into any memory-related issues with just 8 GB.
The Core i7-7500U is a 15W Kaby Lake part with two cores and four threads clocked at 2.7 GHz with a single-core boost frequency of 3.5 GHz. Relative to the Skylake Core i7-6500U, we’re seeing a 200 and 400 MHz increase on base and boost clocks respectively. In my testing, I also observed a brief two-core boost frequency of 3.3 GHz with a sustained boost of 2.9 GHz.
On the graphics side, Intel has moved from their HD Graphics 520 chip to the HD Graphics 620 at the same clock speed of 1,050 MHz. The HD Graphics 620 packs new features, such as 10-bit HEVC encoding and 8-bit VP9 encoding, but as the number of execution units remains the same (24), performance gains shouldn’t be expected.
As for the base model with its Core i5-7200U, you’ll be getting the same two cores and four threads, but clocked at 2.5 GHz with a boost of 3.1 GHz, and a slight decrease in HD 620 graphics frequency to 1,000 MHz. L3 cache has also decreased from 4MB to 3MB.
There are some interesting things to note here about the ZenBook 3’s performance. Firstly, in general, the laptop is around 7 percent faster than both the i7-6500U-equipped Dell XPS 13, and the i7-6600U-equipped Surface Book. This isn’t a massive performance improvement, and it’s entirely due to the faster clock speeds of the Kaby Lake CPU.
However, there are some circumstances where the i7-7500U is not faster than its predecessor. In heavily multi-threaded workloads, Kaby Lake either broken even or recorded a small (1-2%) performance reduction compared to the equivalent Skylake i7-6500U. This is down to the fact that Skylake sustains slightly higher dual-core boost clock speeds: 3.0 GHz rather than 2.9 GHz on the i7-x500U model.
In single-threaded workloads, the 400 MHz increase in boost clock speeds leads to gains of around 16 percent, which is decent. This is where Kaby Lake pulls away from Skylake, and it’s why the ZenBook 3 reports better performance in benchmarks like PCMark.
It’s worth noting that Kaby Lake isn’t going to provide significant increases in encoding performance over Skylake, so unless you’re moving from Core i5 to Core i7, expect similar encoding times in Premiere and other video editing tools. On the flip side, simulation software like MATLAB saw gains of 15 percent, which is down to improved single-core performance.
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