Kaby Lake vs Skylake

When Intel announced Kaby Lake, it quickly became obvious that the traditional tick-tock update cycle was at an end. Kaby Lake is essentially just a ‘tuned’ version of Skylake, but it does bring some important new features with it.

For the unfamiliar, Intel used to operate on a tick-tock schedule which meant that it would (on a tick) introduce a new processor which had a new design (manufacturing process).

Then, the next processor range (the tock) would improve and optimise the same architecture to offer better performance.

Kaby Lake is the effectively the second ‘tock’, improving upon Skylake which was already a ‘tock’ following Broadwell (the tick).

Broadwell was Intel’s fifth-generation of Core processors, but for various reasons never really appeared for desktop PCs, only laptops and laptop/tablet hybrids.

Amazingly, Intel is planning another optimisation of the 14nm architecture, and ‘ Coffee Lake‘ is expected to arrive at the end of the year alongside 10nm Cannonlake.

Although we now know that this kind of extended cycle will be the norm in the future, it’s all rather besides the point of why you’re here, which is to find out the differences between Skylake and Kaby Lake.

Don’t limit your choice to Intel, though. AMD’s Ryzen processors offer a compelling alternative these days.

What are the new features in Kaby Lake?

So we’ve established that the seventh-generation Intel Core processors are fundamentally just optimised sixth-generation chips. For desktop PCs, they both use the same LGA 1151 socket and you can therefore drop a Kaby Lake processor into a motherboard that was running a Skylake chip (and use the same CPU cooler).

However, because Kaby Lake has a few new features, this is generally not a good idea since you’ll miss out as the 100-series chipset doesn’t support them. (And if you do go down that route, then be sure to update your motherboard’s BIOS before you swap chips.)

The best pairing is a Kaby Lake chip and a motherboard with a 200-series chipset. 

4K video

First, Kaby Lake has an upgraded graphics chip which supports encoding and decoding HEVC. This is the latest video codec which is designed for 4K video and it means a Kaby Lake chip will let you watch Netflix, Amazon or any other 4K video in HEVC format without sweating. It also supports VP9 decoding, which is Google’s codec designed to compete with HEVC.

Since the GPU is handling the load here, the CPU cores can be put to use for other things, so your PC won’t grind to a halt while you watch. Also, Kaby Lake supports HDCP 2.2 which, put simply, is the copy protection used for 4K video and you’ll need it to hook up a compatible monitor and watch copy-protected UHD content.

It’s a real boon for laptops, since native support for HEVC and VP9 means the processor doesn’t have to work as hard as a Skylake chip would – it would have to use its CPU cores to decode the video – and therefore battery life should be longer when watching 4K video. Intel says that it can be up to 260 percent better, in fact.

Optane

Second is support for Intel’s new Optane Memory. This is like an NVMe SSD – but faster – and sits in the same M.2 slot on the motherboard. But it’s only compatible with the Z270 chipset, which requires a Kaby Lake CPU (you can run a Skylake processor in a Z270 board but you won’t be able to use Optane Memory).

Performance

Third, Kaby Lake chips perform better than Skylake. Not by a great deal, but there is a slight improvement. Base clock speeds are higher compared to the equivalent Skylake processor, and it’s the same for Turbo Boost frequencies.

Although you’d have to use benchmark tools to notice the difference for most applications, you should have no trouble detecting the improvement in 3D graphics power, at least for the mobile chips.

The Kaby Lake U-series processors (we’ll come to them later) have Intel Iris Plus graphics which promise up to 65 percent better performance than the GPU in equivalent Skylake chips.

Sadly, in the desktop chips, the Intel HD Graphics 630 GPU is largely identical to the 530 found in Skylake. The only real upgrade here is the HEVC and VP9 support.

PCIe lanes

Skylake processors have 20 lanes of communication to the PCH (Platform Controller Hub) but Kaby Lake adds an extra four. With the 16 PCIe lanes on the processor itself, a Kaby Lake system can have 40 PCIe lanes.

USB and Thunderbolt

These extra lanes are important particularly as PCIe is now being used for storage as SATA speeds become too limiting.

Kaby Lake also supports the latest version of USB-C (USB 3.1 Gen 2), which means speeds of up to 10Gb/s rather than 5Gb/s with Skylake. Again, that’s native support without needing a separate controller or add-in card on the motherboard. Similarly, there’s native support for Thunderbolt 3.0.

Kaby Lake systems can have up to 14 USB 2.0 and 3.0 ports and three PCIe 3.0 storage slots.

You can spend up to £550 on a Z270 motherboard such as Asus Maximus IX Extreme, although most are considerably cheaper.

Ultra-low-power Kaby Lake-Y

One confusing aspect is that Intel has rebranded the ultra-low-power Kaby Lake chips, which you’d imagine would be called Core m as they were with Skylake, to Core i3, i5 and i7.

These so-called Y-series chips have a TDP of just 4.5W and offer much, much less performance than their U-series counterparts. They tend to be used in thin and light hybrids such as the Dell XPS 2-in-1 but the ‘Core i’ branding can fool you into thinking you’re getting the same chip as in the XPS 13 laptop.

So watch out for that.

Which is better, Kaby Lake or Skylake?

Clearly, given a choice of two PCs or laptops at the same price – one with a Skylake CPU and one with Kaby Lake – you’d choose the Kaby Lake machine.

For laptops with integrated graphics, you’ll see better performance from a Kaby Lake chip thanks to the Iris Plus GPU and also better performance and battery life when watching 4K Netflix. Indeed, a Skylake-based laptop may not even have the raw CPU power to play 4K video. Then again, not many laptops have 4K screens.