Intel Finalizes Skylake-X Processor Specifications: 18-Cores, 4.4 GHz Turbo, 165W on September 25thby Ian Cutress on August 7, 2017 12:34 PM EST
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:
|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|
|L3||1.375 MB/core||1.375 MB/core|
|Memory Freq DDR4||2400||2666||2666|
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:
|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|
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.
- The Intel Skylake-X Review: Core i9 7900X, i7 7820X and i7 7800X Tested
- The Intel Kaby Lake-X i7 7740X and i5 7640X Review
- The Intel Core i7-7700K (91W) Review
- The Intel Core i5-7600K (91W) Review: The More Amenable Mainstream Performer
- The Intel Core i3-7350K (60W) Review: Almost a Core i7-2600K
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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Bullwinkle J Moose - Monday, August 7, 2017 - link4 cores or 6 for gaming >
For now, 4 cores would seem to be the sweet spot for gaming systems, but if you look at the chart above, the 6 core system is gimped to a lower turbo frequency than the 8 and 10 core CPU's in the X-class systems
Personally, I don't think I will need more than 4 or 6 cores but I wish the lowest core counts had better clocks than the high price / high core cpu's
Lower clock speeds for the 6 core CPU makes no sense
I hope Ice Lake has the best clock speeds on 4-6 core systems
Higher PCIe Lane count on 4-6 core systems would be nice too
Gothmoth - Monday, August 7, 2017 - linkwhen i buy a 16 core system i don´t buy it for single core performance. ROTFL
the base clock of 2.6 GHz is a joke. and no professional worth a dime will be confused by the turbo clocks.
this is just a intel CPU for bragging rights...
HomeworldFound - Monday, August 7, 2017 - linkBut other people would like a jack of all trades. I'd happily upgrade to 12 cores if there was a guarantee of a decent increase in single core performance over the 6 core chip I currently own. Many people here don't just workstation or game or video edit, they do everything.
ddriver - Monday, August 7, 2017 - linkSo I suppose that single thread performance below that of an i7 at 4.3 Ghz is too just too little for "everything"?
Top performance really only matters for time staking tasks such as video editing. It doesn't make any difference if you play games at 150 or 200 FPS, it doesn't matter if a web page loads in 200 msec rather than 150 msec.
After a certain point, single thread performance simply doesn't matter, what matters is having enough, because tasks that require only a single thread are not of critical importance in terms of performance.
IanHagen - Monday, August 7, 2017 - linkThere are some niche areas in which more single threaded performance always matters, but even so... Someone pay this man a pint!
wallysb01 - Monday, August 7, 2017 - link"After a certain point, single thread performance simply doesn't matter, what matters is having enough, because tasks that require only a single thread are not of critical importance in terms of performance."
That's a rather obtuse statement. If say 30% of my work load is in single threaded tasks, while 70% is in multithread, doubling the single threaded performance maters about as much as 1.5x-ing the number of cores.
And for those of us in high core count systems already, we're used to seeing these low base clock rates. The thing is, you're not often in the lowest clock rate, even with all cores active. I'm not sure what the standard with these, but my 2.0 GHz base clock machine (a pair of ivy bridge E5s) is often reporting more like 2.3+ with all cores active. I'd be interested to see if 2.6 GHz is really something closer to 3.0 when people actually get their hands on these processors.
Lolimaster - Monday, August 7, 2017 - linkNo matter what you do, the base clocks of the 1950X will always be 3.4Ghz, that's why intel is totally lost in 2017, they don't have an arch to compete.
Lolimaster - Monday, August 7, 2017 - linkWith intel all thise year, buying a high core count xeon meant having way sub 3Ghz cpu's, not anymore.
nevcairiel - Tuesday, August 8, 2017 - linkThe turbo charts suggest that the 18-core will turbo all cores to 3.4 GHz, but that might exceed TDP in stress-testing situations - although someone building such a system better include a good cooler so they can exceed TDP and possibly even turbo higher then that.
ddriver - Tuesday, August 8, 2017 - linkIf that excludes AVX, then those frequencies do not matter for prosumers. Every prosumer workload out there uses the vector units. The ALU is probably not more than 10% of the entire core performance, and is used mostly for program flow rather than actual data computations.