Kaby Lake-X and Skylake-X processors
Core i9 and Core X series processors
Intel has announced Kaby Lake-X and Skylake-X processors. Where the previous and current Broadwell-E platform had up-to 10 core processors (Core i7 6950X), Intel will expand on that with an up-to 18-core and thus 36-threads processor. Intel markets the news series are the Core X series, and also is adding a new denominator, the Core i9 series. The new processors are paired with a new chipset X299 and socket LGA2066.
A die-shot of the 18-core Skylake-X series processor |
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Kaby Lake |
Broadwell-E |
Kaby Lake-X |
Skylake-X |
|
CPU cores |
4 |
6, 8, 10 |
4 |
6, 8, 10, 12, 14, 16 |
Cache |
8MB |
Up to 25MB |
8MB |
13.75MB |
PCIe support |
PCIe 3.0 (16 lanes) |
PCIe 3.0 (40/28 lanes) |
PCIe 3.0 (16 lanes) |
PCIe 3.0 (44/28 lanes) |
Integrated graphics |
Yes |
No |
No |
No |
TDP |
95W |
140W |
112W |
140W |
Socket |
LGA 1151 |
LGA 2011-v3 |
LGA 2066 |
LGA 2066 |
Chipset |
Z270 |
X99 |
X299 |
X299 |
Memory support |
Dual-channel DDR4 |
Quad-channel DDR4 |
Dual DDR4 |
Quad-channel DDR4 |
Architecture changes
The new Core i9 series processors are based up-on the Skylake architecture that you know from the socket 1151 parts, but merely scaled upwards. The processor series is fabbed at 14nm. Despite being based upon the Skylake architecture, there are some changes to address. IPC has been improved meaning the number of instructions per clock-cycle have been improved. According to Intel, Skylake-X will see an up-to 8% performance increase in IPC. It’s always hard to tell how correct that number is, as Intel in the past simply increase clock frequencies and called that an IPC increase. That, opposed to expensive architecture changes in caches and so on. However Intel did change its caches, the L2 cache for example has been increased from 256 kB towards 1 MB per core, which really is significant. However, relative to that the L3 cache was 2.5 MB and now is 1.375 MB per core, which thus is smaller compared to Broadwell-E. Intel thus tweaked and balanced out the L2 and L3 caches. With the new processors you will also see two Turbo modes dubbed 2.0 and 3.0. We’ll keep it simple, but basically with Turbo mode 3.0 less threads will clock higher. E.g. for a low threaded application a processor could boost with 2 cores to say 4.5 GHz. Whereas Turbo mode 2.0 kick in, it would do say 4 threads at 4.2 GHz.
A New Processor New Socket
The new Skylake-X processor series will bring Socket 2066 towards the new X299 chipset platform. Intel is to release Skylake-X and Kaby Lake-X at the same time. The difference is simple, Skylake-X can offer 18, 16, 14, 12, 10, 8 and 6 core processors (+ threads). The other (Kaby lake-X) remains to be a quad-core part. So Kaby Lake-X processors will physically fit onto the X299, it however ending up being just a dual-channel memory part.
Core i7 7740K |
Core i7 7700K |
Core i5 7640K |
Core i5 7600K |
|
Architecture |
Kaby Lake-X |
Kaby Lake |
Kaby Lake-X |
Kaby Lake |
CPU cores |
4 |
4 |
4 |
4 |
Threads |
8 |
8 |
4 |
4 |
Base clockspeed |
4.2GHz |
4.2GHz |
4GHz |
3.8GHz |
Turbo |
4.5GHz |
4.5GHz |
>4GHz |
4.2GHz |
Cache |
8MB L3 |
8MB L3 |
6MB L3 |
6MB L3 |
Integrated graphics |
No |
Yes |
No |
Yes |
TDP |
112W |
91W |
112W |
91W |
Socket |
LGA 2066 |
LGA 1151 |
LGA 2066 |
LGA 1151 |
Chipset |
X299 |
Z270 |
X299 |
Z270 |
Memory support |
Dual/Quad channel DDR4 |
Dual channel DDR4 |
Dual/Quad channel DDR4 |
Dual channel DDR4 |
A new socket, LGA2066, and yes that means that once again you have to purchase a new motherboard. This chipset will be called X299, it will offer dual-channel memory for Kaby-Lake X processors, and for the Skylake X processors you get quad-channel support (up-to 2667 MHz). And yes, that means from the four to eighteen-core procs, they all will fit the (expensive) X299 motherboards. There are some changes that you will need to be aware of. First off the DMI interface (the IO interconnect in-between the processor and chipset) is getting more bandwidth, roughly 4 GB/s. That means you’ll have more PCIe lanes available for other connections in the IO like SATA, M2, USB and so on-wards.
This is needed as Intel still did not embed USB 3.1 or Thunderbolt 3 inside their processors and thus the motherboard partners rely on external 3rd party chips (and this connection) for such implementations. Kaby Lake-X procs will support dual channel DDR4 and only 16 PCIe 3.0 Lanes, this will be 44 PCIe 3.0 Lanes for the high-end Skylake-X models, not including the 6 and 8-core parts which will get 28 PCIe lanes. The new platform also offers support for Intel Optane.
The Processor line-up
A lot is said and stated about the new line-up, it’s a bit of a confusing series of processors as Intel uses not one, but two architectures (Kaby-Lake-X / Skylake-X and 6 to 18 cores) into one chipset. Next to that we now have to add the Core i9 series, which honestly will see two lines as well, the Core i9 X series and the Core i9 Extreme series. To make things even more confusing, Intel will not launch that 18-core part anytime soon. Perhaps you will see a review in August somewhere, but we expect retail availability to be far from that date. You will see up-to ten core processors released initially with a 12-core part in August. Let's chart things up in a table overview:
What to Expect?
So, what we learned at Computex is that Intel indeed will be releasing just the Skylake-X processors with up-to ten cores initially. All motherboard partners had the 10-core SKU which would be the Core i9 7900X that will be priced at 999 USD. None, and I do repeat this none of the partners have had their hands on, or even seen the 12, 14, 16 or that 18-core part. So that does raise some questions as earlier on we have already stated that Intel is rushing things as an answer towards AMD’s upcoming Threadripper processor series. So on that note, we can confirm that X299 and the respective processors will launch with up-to 10-core processors in the Skylake-X processor series.
That means that there will be three (Skylake-X) SKUs at launch, the Core i7 7800K six core, the 7820X with eight cores and the Core i9 7900K with 10 cores. I highlighted these in the upper overview. The 7740X and 7640X are the Kaby-Lake-X based procs, these are four core processors.
Above the Skylake-X 10-core part, Core i9 7900K on LCS cooling - for all cores locked in at that frequency. Highlighted in the red column is the Cinebench multi-threaded CB score, overclock on all cores that results into 2364cb.