Specifications and Design

We review Intel’s Skylake-X processor with 10 cores!

Intel is at an important crossroads for its consumer product lines. Long accused of ignoring the gaming and enthusiast markets, focusing instead on laptops and smartphones/tablets at the direct expense of the DIY user, Intel had raised prices and only shown limited ability to increase per-die performance over a fairly extended period. The release of the AMD Ryzen processor, along with the pending release of the Threadripper product line with up to 16 cores, has moved Intel into a higher gear; they are more prepared to increase features, performance, and lower prices now.

We have already talked about the majority of the specifications, pricing, and feature changes of the Core i9/Core i7 lineup with the Skylake-X designation, but it is worth including them here, again, in our review of the Core i9-7900X for reference purposes.

Core i9-7980XE Core i9-7960X Core i9-7940X Core i9-7920X Core i9-7900X Core i7-7820X Core i7-7800X Core i7-7740X Core i5-7640X Architecture Skylake-X Skylake-X Skylake-X Skylake-X Skylake-X Skylake-X Skylake-X Kaby Lake-X Kaby Lake-X Process Tech 14nm+ 14nm+ 14nm+ 14nm+ 14nm+ 14nm+ 14nm+ 14nm+ 14nm+ Cores/Threads 18/36 16/32 14/28 12/24 10/20 8/16 6/12 4/8 4/4 Base Clock ? ? ? ? 3.3 GHz 3.6 GHz 3.5 GHz 4.3 GHz 4.0 GHz Turbo Boost 2.0 ? ? ? ? 4.3 GHz 4.3 GHz 4.0 GHz 4.5 GHz 4.2 GHz Turbo Boost Max 3.0 ? ? ? ? 4.5 GHz 4.5 GHz N/A N/A N/A Cache 16.5MB (?) 16.5MB (?) 16.5MB (?) 16.5MB (?) 13.75MB 11MB 8.25MB 8MB 6MB Memory Support ? ? ? ? DDR4-2666

Quad Channel DDR4-2666

Quad Channel DDR4-2666

Quad Channel DDR4-2666

Dual Channel DDR4-2666 Dual Channel PCIe Lanes ? ? ? ? 44 28 28 16 16 TDP 165 watts (?) 165 watts (?) 165 watts (?) 165 watts (?) 140 watts 140 watts 140 watts 112 watts 112 watts Socket 2066 2066 2066 2066 2066 2066 2066 2066 2066 Price $1999 $1699 $1399 $1199 $999 $599 $389 $339 $242

There is a lot to take in here. The three most interesting points are that, one, Intel plans to one-up AMD Threadripper by offering an 18-core processor. Two, which is potentially more interesting, is that it also wants to change the perception of the X299-class platform by offering lower price, lower core count CPUs like the quad-core, non-HyperThreaded Core i5-7640X. Third, we also see the first ever branding of Core i9.

Intel only provided detailed specifications up to the Core i9-7900X, which is a 10-core / 20-thread processor that has a base clock of 3.3 GHz and a Turbo peak of 4.5 GHz (using the new Turbo Boost Max Technology 3.0). It sports 13.75MB of cache thanks to an updated cache configuration, it includes 44 lanes of PCIe 3.0, an increase of 4 lanes over Broadwell-E, it has quad-channel DDR4 memory up to 2666 MHz and it has a 140 watt TDP. The new LGA2066 socket will be utilized. Pricing for this CPU is set at $999, which is interesting for a couple of reasons. First, it is $700 less than the starting MSRP of the 10c/20t Core i7-6950X from one year ago; obviously a big plus. However, there is quite a ways UP the stack, with the 18c/36t Core i9-7980XE coming in at a cool $1999.

Core i9-7900X Core i7-6950X Core i7-7700K Architecture Skylake-X Broadwell-E Kaby Lake Process Tech 14nm+ 14nm+ 14nm+ Cores/Threads 10/20 10/20 4/8 Base Clock 3.3 GHz 3.0 GHz 4.2 GHz Turbo Boost 2.0 4.3 GHz 3.5 GHz 4.5 GHz Turbo Boost Max 3.0 4.5 GHz 4.0 GHz N/A Cache 13.75MB 25MB 8MB Memory Support DDR4-2666

Quad Channel DDR4-2400

Quad Channel DDR4-2400

Dual Channel PCIe Lanes 44 40 16 TDP 140 watts 140 watts 91 watts Socket 2066 2011 1151 Price (Launch) $999 $1700 $339

The next CPU down the stack is compelling as well. The Core i7-7820X is the new 8-core / 16-thread HEDT option from Intel, with similar clock speeds to the 10-core above it (save the higher base clock). It has 11MB of L3 cache, 28-lanes of PCI Express (4 higher than Broadwell-E) but has a $599 price tag. Compared to the 8-core 6900K, that is ~$400 lower, while the new Skylake-X part iteration includes a 700 MHz clock speed advantage. That’s huge, and is a direct attack on the AMD Ryzen 7 1800X, which sells for $499 today and cut Intel off at the knees this March. In fact, the base clock of the Core i7-7820X is only 100 MHz lower than the maximum Turbo Boost clock of the Core i7-6900K!

It is worth noting the performance gap between the 7820X and the 7900X. That $400 gap seems huge and out of place when compared to the deltas in the rest of the stack that never exceed $300 (and that is at the top two slots). Intel is clearly concerned about the Ryzen 7 1800X and making sure it has options to compete at that point (and below) but feels less threatened by the upcoming Threadripper CPUs. Pricing out the 10+ core CPUs today, without knowing what AMD is going to do for that, is a risk and could put Intel in the same position as it was in with the Ryzen 7 release.

Continue reading our review of the Intel Core i9-7900X Processor!

The Core i7-7800X is another interesting part. With a price tag of only $389, it has 6 cores, 12 threads, 3.5 GHz base clock and 4.0 GHz Turbo Boost, 28 lanes of PCIe and the same quad-channel memory interface we see in the processors above it. This CPU is only going to be $50 more than the Core i7-7700K that we see as Intel “mainstream” flagship CPU, a quad-core processor that runs on the Z270 chipset. And at that price, it is $10 UNDER the MSRP of the Ryzen 7 1700X.

The bottom two processors announced today, the Core i7-7740X and the Core i5-7640X are based on a different microarchitecture than the 7 above it. Using the Kaby Lake core, these processors mark the first time we see a split-generation launch for Intel. The Core i7 part is quad-core with HyperThreading, while the Core i5 leaves HyperThreading off, giving us a 4-core / 4-thread LGA2066 CPU for $242. These processors have the same dual-channel memory controller as the Core 7000-series already on the market, and motherboards will have to disable half the DIMM slots when a KBL-X part is installed because of it. They still sport 16 lanes of PCI Express and 8MB/6MB of L3 cache, respectively. They have a higher 112 watt TDP, compared to the 91 watts of their LGA115x brethren.

These are very… interesting CPUs. They do not offer new features compared to the Core i7-7700K or Core i5-7600K, but run at barely higher clocks (100 MHz on the base on the 7740X for example). They don’t see more PCIe integration, they don’t have larger caches. They are basically the same Kaby Lake design we have come to know previously but in a new package and prepped for a new set of motherboards. Is that an advantage? It’s hard to know yet, but in general, the X299 motherboard market is going to be more expensive than the Z270 motherboard market, meaning you are going to pay more in total to own this CPU. Does the added TDP give us more thermal headroom for overclocking? Maybe the new heat spreader? I’m not sure and Intel hasn’t said yet. But what they have stated is that they wanted to offer the option to consumers that wanted the “absolute fastest gaming processor” with the best clock speeds at a reasonable price.

Let’s turn some attention to those higher cost parts, starting at the top. The Core i9-7980XE marks the return of the Extreme designation and becomes the processor with the highest core count announced to date. With 18 cores and 36 threads of compute, despite not knowing the specific clock speeds, I expect it to become the single fastest consumer processor for multi-threaded applications. Though it wasn’t spelled out in the document, we can infer it will have 16.5MB of L3 cache and a 165 watt TDP, creeping into the high end of the Xeon market. That’s really all we know for now – expect that it will run you $1999. No doubt that is ludicrously high for a consumer part, but it is tempered by two facts.

First, the Xeon equivalent of this processor is going to be more expensive. I don’t know by how much just yet, but the Xeon E5- 2697V4 is an 18-core / 36-thread processor with a tray price of $2700. That means the Core i9 part with similar performance specs will be at a significant discount by comparison. The second point is that the 10-core Broadwell-E processor launched last year at $1700. Now Intel is offering you 8-more-cores for “only” $300 more.

Today we now know that Intel is only releasing the 10-core Core i9-7900X, 8-core Core i7-7820X and 6-core Core i7-7800X and the Kaby Lake-X 4-core CPUs on June 26th. The 12-core processor will be shipping in August with the 14, 16 and 18-core expected to ship sometime in October. That leaves the 10-core/20-thread 7900X as the top end HEDT SKU from Intel for the foreseeable future but also leaves the window open for AMD to release Threadripper with 16-cores and take wind of any sails that Skylake-X might provide for Intel. (Editor’s Note: we are expecting a quad-core processor for this platform very soon and we will post a review up on that ASAP.)