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The Intel Core i9-7900X 10-core Skylake-X Processor Review

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Subject: Processors
Manufacturer: Intel

Specifications and Design

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!

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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.

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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.

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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.)


June 19, 2017 | 10:04 AM - Posted by Martin Trautvetter

A 15% increase in performance resulting from a 50% increase in power consumption seems to indicate that this processor is firmly out of its comfort zone in terms of efficiency.

Makes me wonder where it would land with similar clock rates as the 6950X.

As for the i9 line-up, I don't follow the argument that these CPUs are not the direct result of AMD's renewed competitiveness. Sure, 6- through 10-core CPUs would've been planned for long ago, but their final clocks were set post-Ryzen. The idiotic KBL-X were rushed post-Ryzen. The MCC-i9s are clearly a rush job (hence their late launch) trying to compete with Threadripper.

I'd be willing to bet that not a single CPU launched for this platform was planned exactly as-is 9 months ago.

June 19, 2017 | 10:48 AM - Posted by Ryan Shrout

Even if everything you say is true, is that a problem? Is that not what we want? Some competition to push things forward?

June 19, 2017 | 12:39 PM - Posted by Martin Trautvetter

Sorry, I might have simply misread/misunderstood your conclusion.

As far as I'm concerned, it was not giving enough credit to AMD for the final specs of these CPUs, as they are / will be shipping.

Anyways, thanks for testing the rejiggered cashes and mesh topography and showing how it affects scaling when compared to its predecessor!

June 19, 2017 | 11:02 AM - Posted by Xebec

I am curious if future BIOS updates will affect mesh speed(ping time?), and what kinds of differences that will make.

I like the performance/$ metrics. There's so many ways to slice those -- CPU Only, including motherboard and RAM (which you have to buy anyway to use the CPU), or full system price. Pros/Cons to each.

Best internet line of the day:
"Until July. Or August. Or October..."

Great review PCPer!

June 19, 2017 | 11:13 AM - Posted by Ryan Shrout

Future BIOS should not have a direct effect on it, unless Intel changes its stance on the clocks of the cache. It runs at a slower clock that memory or the CPU itself, but it is controllable - I show you the change on one of our graphs here looking at thread to thread "ping times".

On the performance / dollar, you are right, we could have included memory and motherboard in that and it might be worth doing in the future. But I think most people reading will understand that the X299 motherboard price average is higher than the X370 motherboard price average, so the differenecs will widen slightly.

June 24, 2017 | 08:40 PM - Posted by RandomUsername1234 (not verified)

X370 may not be a fair yardstick if you want price/performance. X370 is closer to X299 in features (though still a long way off), but if want you want is maximum price/performance B350 is the way to go.

June 19, 2017 | 11:19 AM - Posted by DakTannon

Hey Ryan great review. If possible for the gaming benchmarks could you post the 1% and .1% low frame rates or just the min fps if that would be easier. I have found the enthusiast platform tends to excel in the minimum FPS and smooth delivery of frames (less stutter) and that is what motiveates my purchases more than Max or Average fps i would rather have a CPU with a min of 60 fps and a max of 85 fps than one with a max of 105 fps and a min of 45 fps even if that mean it has a lower average fps, smoothness is everything for me

June 19, 2017 | 02:59 PM - Posted by StephanS

At what speed where you running the 1800x infinity frabic ?

Also your idle system wattage look to be half of other sites for the 1800x. I wonder what you or they are doing differently.

Cinebench value. Not sure why but I get a score of 1641 on a stock 1800x. / $440 (amazon) = 3.72
I think you are using the launch day price of $500 ?

note: I run my ram at 2400mhz (the rated XMP profile)

June 19, 2017 | 03:18 PM - Posted by Ryan Shrout

All of the 1800X data was generated at stock settings, DDR4-2400 memory. And yes, I am still using the $499 launch price for that data, as you note.

June 19, 2017 | 03:10 PM - Posted by amadsilentthirst

Great Video Ryan, Actually made me read the review... that was good too.

With....one little exception New parts, higher clocks, more cores

Kinda wanted to see what the "NiceHash" daily BTC amount would be, you know for science.

Consider including it in your benchmarks for all the new CPU's?

June 19, 2017 | 03:18 PM - Posted by Ryan Shrout

Maybe...but CPUs, even 10-core CPUs, are very inefficient in comparison to even moderate GPUs.

June 19, 2017 | 03:52 PM - Posted by amadsilentthirst

You are totally right, and rather handsome,
However after Electrickery a Ryzen 7 1700X nets $600 per annum

Which is peanuts to golden haired tech gods granted, but some peeps may want to put one in a corner and let it pay for itself (with all the assumptions granted) while heating up their greenhouse.

As alogs change and prices fluctuate, releases get more cores, it'll be nice to keep an eye on hashing value.

Goes without saying that it will be awesome to have it on GPU charts.

You're obviously way too important and tall to take on such a task, maybe the smaller more condensed you (Ken) could take on such a burden of honour.

June 19, 2017 | 04:53 PM - Posted by quest4glory

Something I haven't seen much of is the (potential) benefit of this X299 plan to boutique system builders, and even larger mass producers of custom PCs such as HP with their Omen, and Dell / Alienware.

They could standardize on X299 for most of their builds, and then offer customers the choice of i5 and "entry level" i7 now, with the option to upgrade to a true HEDT system later on, while keeping the same chassis and main system components.

That and single-core performance should be best on those parts, especially when overclocked to their max.

June 19, 2017 | 05:53 PM - Posted by quest4glory

In terms of TDP, did you measure that at stock or overclocked? I'd have to assume stock, and if so, could the measurements be off due to the new platform?

I know you know this, but for anyone who wonders how Intel defines TDP...from https://www.intel.com/content/dam/doc/white-paper/resources-xeon-measuri...

"Intel defines TDP as follows: The upper point of the thermal profile consists of the Thermal Design Power (TDP) and the associated Tcase value. Thermal Design Power (TDP) should be used for processor thermal solution design targets. TDP is not the maximum power that the processor can dissipate. TDP is measured at maximum TCASE.1"

June 20, 2017 | 04:40 PM - Posted by Ryan Shrout

All measured at stock settings.

June 19, 2017 | 06:15 PM - Posted by Titan_Y

Seems to me that there has been a cost-shift Intel has done here from the CPUs to the chipsets. The motherboards are about $100 more expensive than they should be. This way, Intel can make their CPUs out to be a better value than they actually are.

June 19, 2017 | 10:11 PM - Posted by Ryan Shrout

I don't think that's accurate. Intel is probably getting slightly more from the X299 than the Z270, but I would guess not much. If anything, the motherboard vendors know this is a higher end platform and audience, so they put higher end products together to serve it.

June 19, 2017 | 11:07 PM - Posted by boinc_oclock

Ryan,

Did overclocking the cache + using faster RAM have any effect on benchmarks?

June 19, 2017 | 11:50 PM - Posted by Ryan Shrout

I honestly did not have time to check, only to do the latency evaluation you saw on that page. We'll be following up - my expectation is that it will have affect on things like 7zip and the 1080p gaming results, if it all.

June 22, 2017 | 10:16 PM - Posted by boinc_oclock

I'm looking at Guru3D's X299 motherboard reviews and it seems like the BIOS that run the more conservative power profile have higher memory/L3 latency and run worse in games and synthetics like Cinebench. The Cinebench scores matched your results so I'm assuming these latency tests were done using the lower power profiles.

It will be interesting to see what your latency tester shows on the higher power profiles.

June 20, 2017 | 04:08 AM - Posted by chortbauer

Great Review!

Grammar Nazi:
On the last page, under the last picture


It is worth noting here that our early testing with the X299 motherboards has including troubling amounts of performance instability and questionable compatibility.

June 20, 2017 | 04:41 PM - Posted by Ryan Shrout

Ah, thanks. :)

June 20, 2017 | 04:27 AM - Posted by n19h7m4r3

Interesting to see the Intercore latency affect Skylake X so much. Despite Ryzen's latency affecting games, it does compete well with Broadwell often, despite lower clocks usually.

It's nearly the reverse in gaming with Skylake X, where it's clocked higher, and still loses.

I hope Ryan does some detailed tests with Skylake X X CPUs, and Threadripper to see how the increase CPUs & CCX's will affect latency; and as a result affect some use cases.

June 20, 2017 | 06:40 AM - Posted by psuedonymous

"And to combat Threadripper, it seems clear that Intel was willing to bring forward the release of Skylake-X, to ensure that it maintained cognitive leadership in the high-end prosumer market."

Impressive Intel know the release date for Threadripper back in 2015 when they scheduled Basin Falls! https://regmedia.co.uk/2015/05/26/intel-kdm-roadmap-1.jpg

August 19, 2017 | 04:10 AM - Posted by Desmond (not verified)

Continue the good work; keep posting more n more n more.
seo service cambridge

June 21, 2017 | 01:10 AM - Posted by Cellar Door

Hey Ryan,

Great job as always! Just wanted to give a little feedback about the graphs - the font is borderline unreadable and that is on a 1080p 27" ultrasharp Dell.

Otherwise keep on rocking!

June 24, 2017 | 11:19 AM - Posted by Anonymous123 (not verified)

Why is your latancy test different to that from sysoft Sandra?

http://www.tomshardware.de/performance-benchmarks-ubertaktung-leistungsa...

Intel 7900x
Sisoft: 79ns
PCPer: 100ns

AMD Fabric:
Sisoft: 122
PcPer: 140

June 24, 2017 | 08:15 PM - Posted by RandomUsername1234 (not verified)

Perhaps you guys should factor in the platform cost in these reviews - B350 Mobos can be had for ~$100, while these X299 Mobos cost at least $400. It's hard to argue the i7-7800X is a suitable competitor for the 1700 when you have to pay another $400 for the motherboard, and are still two cores short (though the higher clocks make up for this)

Intel needs to offer multi-core mainstream offers to truly compete with the 1700 in the future. Right now higher clocks trump twice the threads, but if games like Battlefield and the higher core count of consoles are anything to go for that won't last forever.

June 24, 2017 | 08:15 PM - Posted by RandomUsername1234 (not verified)

Perhaps you guys should factor in the platform cost in these reviews - B350 Mobos can be had for ~$100, while these X299 Mobos cost at least $400. It's hard to argue the i7-7800X is a suitable competitor for the 1700 when you have to pay another $400 for the motherboard, and are still two cores short (though the higher clocks make up for this)

Intel needs to offer multi-core mainstream offers to truly compete with the 1700 in the future. Right now higher clocks trump twice the threads, but if games like Battlefield and the higher core count of consoles are anything to go for that won't last forever.

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