When Intel launched its new high-end desktop platform a few weeks ago, we were provided with Core-X CPUs from quad cores on the latest Kaby Lake microarchitecture, and 6/8/10 core parts on the Skylake-SP microarchitecture derived from the enterprise line and taking a different route to how the cache was structured over Skylake-S. At the time we were told that these latter parts would be joined by bigger SKUs all the way up to 18 cores, and up to $2000. Aside from core-counts and price, Intel was tight lipped on the CPU specifications until today.

Skylake-X goes HCC

The original Skylake-X processors up to 10 cores used Intel’s LCC silicon, one of the three silicon designs typically employed in the enterprise space, and the lowest core count. The other two silicon designs, HCC and XCC, have historically been reserved for server CPUs and big money – if you wanted all the cores, you had to pay for them. So the fact that Intel is introducing HCC silicon into the consumer desktop market is a change in strategy, which many analysts say is due to AMD’s decision to bring their 16-core silicon into the market.

Both the new HCC-based processors and the recently released LCC-based processors will share the same LGA2066 socket as used on X299 motherboards, and all the processors will differ in core count, with slight variations on core frequencies, TDP and price.

The Skylake-X line-up now looks like:

Skylake-X Processors
  7800X 7820X 7900X   7920X 7940X 7960X 7980XE
Silicon LCC   HCC
Cores / Threads 6/12 8/16 10/20   12/24 14/28 16/32 18/36
Base Clock / GHz 3.5 3.6 3.3   2.9 3.1 2.8 2.6
Turbo Clock / GHz 4.0 4.3 4.3   4.3 4.3 4.3 4.2
TurboMax Clock N/A 4.5 4.5   4.4 4.4 4.4 4.4
L3 1.375 MB/core   1.375 MB/core
PCIe Lanes 28 44   44
Memory Channels 4   4
Memory Freq DDR4 2400 2666   2666
TDP 140W   140W 165W
Price $389 $599 $999   $1199 $1399 $1699 $1999

Along with this, we have several release dates to mention.

  • The 12-core Core i9-7920X will be available from August 28th
  • The 14-18 core parts will be available from September 25th (my birthday…)

On the specification side, the higher-end CPUs get a kick up in TDP to 165W to account for more cores and the frequency that these CPUs are running at. The top Core i9-7980XE SKU will have a base frequency of 2.6 GHz but a turbo of 4.2 GHz, and a Favored Core of 4.4 GHz. The turbo will be limited to 2 cores of load, however Intel has not listed the ‘all-core turbo’ frequencies which are often above the base frequencies, nor the AVX frequencies here. It will be interesting to see how much power the top SKU will draw.

One question over the launch of these SKUs was regarding how much they would impinge into Intel’s Xeon line of processors. We had already earmarked the Xeon Gold 6154/6150 as possible contenders for the high-end CPU, and taking the price out of the comparison, they can be quite evenly matched (the Xeons have a lower turbo, but higher base frequency). The Xeons also come with multi-socket support and more DRAM channels, at +60% the cost.

Comparing against AMD’s Threadripper gives the following:

Features Intel Core
Intel Core
AMD Ryzen
Threadripper 1950X
Platform X299 X299 X399
Socket LGA2066 LGA2066 TR4
Cores/Threads 18 / 36 16 / 32 16 / 32
Base/Turbo 2.6 / 4.2 / 4.4 2.8 / 4.2 / 4.4 3.4 / 4.0
GPU PCIe 3.0 44 44 60
L2 Cache 1 MB/core 1 MB/core 512 KB/core
L3 Cache 24.75 MB 22.00 MB 32.00 MB
TDP 165W 165W 180W
 Price $1999 $1699 $999

We fully expect the review embargoes to be on the launch dates for each CPU. Time to start ringing around to see if my sample was lost in the post.

Related Reading

Update on 8/8:

Due to some sleuthing, PCGamer managed to obtain turbo frequencies based on per-core loading. I'm surprised Intel doesn't give this data out like candy when the products are announced, but we're glad to have it nonetheless.

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  • ddriver - Tuesday, August 8, 2017 - link

    "But the 7820X required the rather significant 60 % of EXTRA POWER power to beat the 1800x by the measly 6.7%."
  • MLSCrow - Wednesday, August 9, 2017 - link

    Yes, in the benchmarks that came out when Ryzen was launched, Skylake definitely outshined Ryzen in all but multi-threaded applications as single core IPC is much higher on Intel cores. However, when Ryzen was launched, there were some initial bugs that needed to be ironed out before Ryzen's performance could really come through. One such bug is RAM. Most of the initial reviews couldn't seem to get RAM working past 2133MHz in most cases. Sometimes, you'd get 2933MHz, but generally, RAM had to be down-clocked or much slower sticks needed to be used.

    The architecture of Zen is such that RAM speed greatly affects performance, unlike in an Intel system. Since the Infinity Fabric is linked to RAM speeds, the advantage of using faster RAM in a Ryzen based system is unique in a remarkable way. Upwards of 40% performance increases can be achieved simply by using 3600MHz RAM over 2133MHz.

    Outside of RAM is the fact that most software doesn't have Zen optimizations built in to them. Those will come out increasingly with time and as we've all seen, from a 1st-round version of an optimizationpatch, performance increases of greater than 30% can be had. Who knows how much additional performance can be squeezed out with further optimization patches.

    We've also seen some additional tweaks that have been discovered with regards to RAM timings and various other features which, depending on whether or not they are turned on or off, combined, can add up to a 9-10% performance increase. Collectively, that's almost 80% performance that can be added to some of the original benchmark numbers.

    That all being said, Ryzen clocked at 3.965GHz using DDR4-3600MHz, was able to outperform the i7-7700K clocked at 5GHz in many games that the 7700K outperformed it and many of which still did not have any form of Ryzen optimizations released.

    Again, take note, a 7700K at 5GHz! And in games that the 7700K previously won, meaning games that don't necessarily utilize the additional cores that Ryzen offers.


    I think that the Zen architecture is much better than most people give it credit for. Ryzen is a first edition of a brand new arch, and with that, there will obviously be some bugs, unforeseen issues and limitations, and various issues that may not be able to fully unleash the architectures capability, but with time, I feel that we'll all start to see just how good the Zen arch can actually be.
  • Total Meltdowner - Thursday, August 10, 2017 - link

    u a faggot nig g3r
  • Icehawk - Tuesday, August 8, 2017 - link

    If 100% of your cores are running at 100% load 24-7-365 you likely did not properly size your server (yes there are tasks where this would be acceptable but, IMO, still not optimal).
  • Total Meltdowner - Thursday, August 10, 2017 - link

    This is a very good point.
  • twtech - Friday, August 11, 2017 - link

    With sufficient cooling, you can achieve the all-core turbo frequency all of the time. That's why it's important to find out what it is.
  • dgingeri - Monday, August 7, 2017 - link

    I'd be willing to bet they release a WS version of Xeon using much the same specs as here, clock locked, and socket 2066.
  • cekim - Monday, August 7, 2017 - link

    Odd, that the 6154 (3.7 all-core turbo xeon) has a 205W TDP??? Yet, this is 165W for 18 cores @ 4.2 Turbo? More shenanigans with TDP (SKLX's TDPs have been "suggestions" or "aspirational" so far)? Or has something been turned off?
  • ilt24 - Monday, August 7, 2017 - link

    The Xeon Xeon 6154 is listed as having a 200W TDP with base of 3.0 Ghz and max turbo of 3.7Ghz. Intel also have a Xeon 6150 which is listed with a 165W TDP, 2.7Ghz base and max turbo of 3.7Ghz.

    Looking at those two, it seems the reason the 6154 would has a higher TDP than the i9-7980XE is the higher base clock.
  • cekim - Monday, August 7, 2017 - link

    Again, odd choice, but you are correct, it appears they've chosen the 6150 as the donor line for this chip when 3.0 would have been a more suitable base block for a desktop chip and 200W entirely reasonable given the target market. I supposed MB VRM limits already in place could have made that choice.

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