
The Intel Skylake-X Review: Core i9-7900X, i7-7820X and i7-7800X Tested - jsheard
http://www.anandtech.com/show/11550/the-intel-skylakex-review-core-i9-7900x-i7-7820x-and-i7-7800x-tested
======
bhauer
The 7740X retaining dominance in browser-oriented tests demonstrates the
continued bottleneck we suffer due to the "single-threaded" (or nominally
single-threaded) predilection of web browsers, the DOM, and JavaScript. Servo
and other concurrency-oriented innovations are going to be very welcome when
they arrive in earnest.

~~~
bo1024
I don't understand why anyone would design a website so complex that there is
a noticeable benchmark difference between $100 processors and $1000
processors.

~~~
examancer
The view that web apps can only be for simple things is a dated perspective,
but also probably a symptom of the fact that it's not really possible to take
full advantage of many CPU cores in a web application.

An in-browser photo editor or 3D modeling software would be expected to run
much better and apply complex effects or render models much faster on high-end
hardware. It sort of works this way with WebGL content, but even there you're
limited to feeding the render pipeline with a single thread.

I want the web as a platform to succeed. It is the only truly universal
runtime and with some care it could offer very few performance trade-offs. I
sincerely hope tools like servo and others unlock this potential.

~~~
Gravityloss
From first principles, one shouldn't expect the menus or other simple rendered
parts (things not involving backend traffic) of a user interface to have any
perceptible lag on a sub-100 processor, be it an application for web, mobile
or desktop. Most likely they shouldn't involve millions of computations or
hundreds of megabytes of memory reads.

But looking from the other end, somehow they definitely do. And we're probably
wasting trillions on this problem. Wasted time, wasted electricity, wasted
batteries, wasted computers and phones.

------
faragon
TL;DR: Intel is having hard time to keep up against AMD. It reminds me the
Pentium 4 era, when Intel had to push clock and power consumption to crazy
levels [1]

[1] [http://www.anandtech.com/show/11550/the-intel-skylakex-
revie...](http://www.anandtech.com/show/11550/the-intel-skylakex-review-
core-i9-7900x-i7-7820x-and-i7-7800x-tested/8)

~~~
paulmd
It's a pretty natural consequence of how much crap Intel piled in on this
release. Cache, mesh, and AVX512 all consume a great deal of power.

Contrary to what the sibling comment says, Ryzen is nowhere near Intel's
performance here. Even in very parallel tasks like x264 video encoding, the
7800K (6-cores) is beating the highest-clocked 8C Ryzens by almost 6%.
Comparing apples to apples, the 7820X (8C) is 33% faster than the 1800X.

That's a very good place for Intel to be overall, even if their power
consumption is higher than I'd like to see. Downclocked Xeons will probably
beat Ryzen's efficiency. And there may be some UEFI/microcode gains to be made
here as well, both in efficiency and total performance.

The bigger problem (for the enthusiast market) is the thermals. Intel just
switched from solder to TIM on the HEDT processors and it's very clear that
they cannot move heat out of the package fast enough and it's limiting the
total OC, which would likely reach 5 GHz a good chunk of the time.

[http://i.imgur.com/9e8Trr3.png](http://i.imgur.com/9e8Trr3.png)

~~~
faragon
33% faster encoding x264, at what price? Ryzen 7 1800X: $499, Core i7-7820X:
$599 (+20% over Ryzen). You can also cherry-pick tests where the Ryzen gets
better performance or better performance/price, and not just tests involving
AVX usage. Also, in cheaper Ryzen's the performance/price gets abysmal in
favor of AMD. BTW, you can compare also a $599 GPU performance encoding x264
versus that Intel CPU and see how "fast" are Intel CPUs in comparison.

~~~
voltagex_
Are there any GPU x264 encoders that don't look like garbage compared to
ffmpeg -c:v libx264 -preset veryslow -crf 18?

~~~
paulmd
No, when I encode my vidya sessions for archival I use 1440p variable-fps
(60fps) NVENC H264 for the first pass at an absurd bitrate (40mbps) and then I
use x264 variable-fps veryslow CRF 24 for the archival pass.

veryslow is where the magic happens. As far as I can tell that's where you
start getting decent quality/compression. If I increase CRF any higher
(decrease quality) then shit gets super blocky super fast. Unfortunately I
haven't found a way to crush high-quality streams like that in remotely
realtime, you need to record 1440p (and dump an archival stream to disk) and
then transcode to 1080p since that's doable.

------
vosper
In the meantime, the 6 core Broadwell-E I7-6850K has seen a big price drop -
down from $650 to $480 on several sites. It's still expensive compared to the
Kaby Lake I7-7700K, but if you wanted two more cores then it's now a much more
reasonable option. People seem to have very good results overclocking it, too.

Edit: Having just seen that the i7-7800X is priced at $389, I'm thinking the
I7-6850K is still overpriced, unless you need 40 PCI-E lanes.

~~~
jhasse
Why not go with a Ryzen 7 1700 instead if you want more cores?

~~~
icelancer
I looked into this and was going to buy a Ryzen or wait for the Threadripper
for a huge multicore video transcoding server we run, in an attempt to source
parts for an upgrade for our last-gen i7 platform. Unfortunately Ryzen's
performance in ffmpeg is dismal, relating to its poor AVX performance, it
seems.

I've seen comments on their platform being "poor" due to software not tuning
for the platform specifically, which is definitely possible. But unfortunately
I can't bank on that for now, so we had to stay with Intel for our batch
transcoding processes. Still very excited to monitor this product line; it's
been a long time coming.

[https://www.phoronix.com/scan.php?page=article&item=ryzen-18...](https://www.phoronix.com/scan.php?page=article&item=ryzen-1800x-linux&num=5)

[http://www.pcgamer.com/the-amd-ryzen-7-review/4/](http://www.pcgamer.com/the-
amd-ryzen-7-review/4/)

~~~
vaeinae
That Phoronix FFmpeg test clearly measures 2 - 4 threaded speed only, so
Intel's fast quad core CPUs shine there. The test description is "H.264 HD to
NTSC DV" where the main bottleneck is slow H.264 decoding (CABAC decoding is
somewhat difficult to parallelize).

You should look for x264 (H.264/AVC encoding) or x265 (H.265/HEVC encoding)
tests. HandBrake is often used as a frontend for these, so the test may be
named Handbrake H.264 HQ encoding or something like that.

x265 benefits a bit more from Intel's faster AVX instructions, but Ryzen (or
Threadripper/Epyc) is still a very valid choice for high quality HEVC
encoding. The GPU alternative would be Intel Skylake's GPU-accelerated encoder
through Media Server Studio, which has scored well in MSU's test:
[http://compression.ru/video/codec_comparison/hevc_2016/](http://compression.ru/video/codec_comparison/hevc_2016/)

As for H.264 encoding, there are no GPU encoders that could approach x264
quality.

~~~
icelancer
Great post. I can tell you my benchmarks using GPUs and various platforms
didn't favor x264 encoding, as you also noted.

>x265 (H.265/HEVC encoding)

Not something our services can reasonably support or use currently, so even if
true, Ryzen/Threadripper is still probably not something we can go with.

I look forward to switching in 2-3 years when we re-visit this conversation,
or adopting it for other services soon. I'm very excited for AMD's competition
and fully willing to switch; I just haven't seen the evidence that supports
that it would be a good idea for our particular use case.

------
Symmetry
I'm surprised at how well Ryzen is holding up in FP terms despite the relative
lack of flops on paper. I guess having a separate floating point cluster is
enough of an advantage to make up for that? It really makes me want to see how
it works with robot motion planning at work.

------
dis-sys
Saw some test results on Chinese website claiming that once fully loaded the
temp can jump to 100+ degrees when running at stock frequency without any form
of overclocking.

It that true?

[http://img1.mydrivers.com/img/20170620/0ff9382549894c64a9989...](http://img1.mydrivers.com/img/20170620/0ff9382549894c64a9989e9d578c3e7e.jpg)

~~~
en4bz
These are the first Intel HEDT chips to not have a soldered heat-spreader.
Instead they are using thermal paste between the chip and the heat-spreader.
This is generally accepted to be bad practice since they use cheap paste and
it's dependent on how the paste was spread on each chip. I also believe that
Intel has basically said water cooling is a must for these chips.

~~~
dom0
Well anandtech already found that water cooling is simply insufficient to cool
these for overclocking. You _need_ an active thermal sink AKA a compressor
cooler, and then you're still limited by the TIM-gunk; heat-spreader at 25 °C,
core at 100 °C.

I suppose for the next generation Intel will announce that liquid nitrogen is
basically required.

~~~
TomMarius
Usage of liquid nitrogen would put us just a few steps away from achieving
superconductivity... Thanks Intel, I guess?

------
bratao
I´m surprised to see how the AMD Ryzen are still holding on the benchmarks

~~~
noir_lord
I've got a Ryzen 1700 I built for work, it's so good I'm shifting up my
upgrade at home to back of this year and looking hard at the 1700X.

It's just fantastic at the price point.

~~~
HNaTTY
My 1700x build for video processing has suffered major instabilities -- app
crashes and BSODs -- memory corruption type errors. I went through 4 different
types of DDR4 memory until I found some that works, even though it isn't on
the ASUS's Qualified Vendors List. My advice is to make sure your RAM can do
15-15-15-36 timings (or better).

~~~
setq
This is why I'd rather lose 25% of the performance these days and take a
canned pre-built PC. I just can't afford the time to find this out. It was bad
enough trying to find a working set of drivers for my T440 and that only took
an hour or so.

I lived through the age of self build K6's, Athlons, dual Celerons and SLI
Voodoo 2's and heatsinks the size of a can of coke. I'd rather just have a
shitty old thinkpad and a box in AWS now. This all happened when I realised a
naff old Pentium III 1.4 GHz (Compaq AP230) was actually my goto machine
despite having things 3-5x the speed.

I run a fair few high CPU/RAM simulations with LTspice as well for ref.

~~~
michaelmrose
Wouldn't buying memory on the motherboard makers list also have served to save
said time?

~~~
setq
Not necessarily as on at least two times in the past, it didn't work properly
without frigging around with timings.

~~~
michaelmrose
Been building pcs since 2003. Always bought known to be compatible ram never
had an issue with ram. Received a defective motherboard once ever.

------
osmala
i7 7820X is the CPU is probably the best system price/performance overall in
the long run right now. Threadripper might be competing it depending on what
you do but we don't know about it yet. For software developers having over 50%
lead in compilation performance compared to ryzen 7 1800X (nightly build of
chromium on visual studio) should make it a good choice.

A) In system price there are many components and that makes ultra cheap CPU:s
in other vice identical configurations not so good price-performance.

B) Performance is really the performance differential from what you upgrade.
And even more importantly the performance differential years from now to
systems of that time, if you upgrade to a system that lasts 5 years before you
upgrade or to a system that lasts 7 years before you upgrade is significant in
terms of price/performance because later means you get the high performance
early and price last longer.

C) Significantly higher single threaded performance compared to Ryzen 7 the
main contender. There are still many tasks that are single threaded,
especially if you run legacy code.

D) AVX-512 I doubt the review benchmarks are in AVX-512 but some legacy code.
AVX-512 increases both width of vector and fraction of code and algorithms
that can be parallerized significantly. Once compilers are well tuned to use
AVX-512 the code compiled with AVX-512 optimizations turned on should be
significantly faster than what it was before hand. Simply being able to do
8-16 times work per cycle in large variety of tasks is significant advantage
even if that is for a good fraction of time instead of all the time.

Personally I7-920 has given me far better price-performance compared to people
who bought dual core at the time simply because it has lasted LONGER so it had
superior price/(time between CPU upgrades) measurement. Right now in that same
measurement I7-7820X is the king.

So in conclusion I7-7820X is faster in both real legacy code and the future
code, and gives good enough performance longer simply because code that you
run when you would start considering upgrades run much faster on it simply
because of extensions.

------
satai
Any idea, why is Intel so much better at Chrome compilation?

~~~
IanCutress
The chrome compile test doesn't like L3 victim caches. Ryzen does badly as a
result. Clock for Clock the Skylake-SP cores do bad as well, but Skylake-X is
well clocked with cores, so it's still top of the charts.

~~~
dom0
But Skylake-X has a victim LLC now as well...

... I'd suspect the memory channels here.

~~~
IanCutress
Skylake-X has double the L2 cache, double the DRAM channels, more cores and a
higher frequency. They compensate :)

------
gbrown_
Nice to see a breakdown of the myriad of AVX-512 instruction sets. This isn't
something Intel was saying much about prior to official launches.

~~~
dogma1138
This is something Intel has said for over 2 years now, AVX512 has several
instruction sets under it. CD is probably the biggest gamechanger since it now
allows you to vectorize code that you couldn't before due to memory conflicts
that arise from identical elements in the array.

But the difference between Skylake-EP/X and XeonPhi in relation to AVX-512
support were known way in advance.

~~~
gbrown_
> But the difference between Skylake-EP/X and XeonPhi in relation to AVX-512
> support were known way in advance.

I don't think differences in specific instructions were known in advanced, at
least at/ shortly after KNL launch. Or rather I was instructed not to mention
it.

~~~
dogma1138
[https://en.wikipedia.org/wiki/AVX-512#New_instructions_in_AV...](https://en.wikipedia.org/wiki/AVX-512#New_instructions_in_AVX-512_foundation)

The instruction set info on that page is 2-3 years old, nothing has changed
since then.

I've seen those tables at least a year before the KL launch they were also
available on Intel's webiste (the blog irrc) at least a year before KL.

I don't know who told you that that information is embargoed.

EDIT: The inital table was here: [http://software.intel.com/en-
us/blogs/2013/avx-512-instructi...](http://software.intel.com/en-
us/blogs/2013/avx-512-instructions) the blog post no longer exists, try
archive.is

[https://software.intel.com/en-us/articles/performance-
tools-...](https://software.intel.com/en-us/articles/performance-tools-for-
software-developers-intel-compiler-options-for-sse-generation-and-processor-
specific-optimizations) "The instruction groups common to both the Intel Xeon
Phi processor x200 and the Intel Xeon processor are AVX-512F and AVX-512CD.
The AVX-512ER and AVX-512PF groups are implemented in the Intel Xeon Phi
processor x200 only. The AVX-512BW, AVX-512DQ and AVX-512VL groups are
implemented only in the Intel Xeon processor."

[https://software.intel.com/en-us/blogs/additional-
avx-512-in...](https://software.intel.com/en-us/blogs/additional-
avx-512-instructions) This used to lead to a PDF with the tables, the PDF is
still there but it's a living document which is updated every time, the latest
revision was in 2017 but as early as 2014 there was already a split into
COMMON-AVX512, MIC-AVX512, CORE-AVX512 with a difference between future Xeon
Phi and Xeon processors.

------
drzaiusapelord
Looks like we're back to P4-style levels of power use. Not sure how I feel
about consumer chips running 150 watts on the regular. That's a lot more
carbon in the atmosphere for questionable reasons.

[https://www.pcper.com/reviews/Processors/Intel-
Core-i9-7900X...](https://www.pcper.com/reviews/Processors/Intel-
Core-i9-7900X-10-core-Skylake-X-Processor-Review/Power-Perf-Dollar-Conclusi)

Incredibly, the 7900X is hitting 240 watts. When was the last time we had a
chip that burned that much energy? Granted, its destined for the server room,
but a 2U quad CPU box will be hitting 1000 watts on CPU usage alone at 100%
utilization. That's close to a medium-sized window AC unit.

~~~
BuckRogers
Yes, those TDPs made them dead on arrival for me. I moved to mini-ITX for my
main system and won't be going back. There's no room in my case for any
watercooling hardware. I run a Ryzen 7 1700 which is a 65W TDP 8 core, 16
thread CPU.

I was going to hold off for Intel's response, but I knew they wouldn't have
anything with 8 cores that was anywhere near 65W TDP. CoffeeLake should offer
lower TDPs, but with 6 cores max which seems unappealing compared to 8C.

I'm going to revisit Intel after they've had time to prepare a real response
to Ryzen in ~2020 or so.

~~~
mcraiha
You can put watercooling pump and radiator outside of your case.

~~~
loeg
Kind of defeats the point of mini-ITX, though, for some of us.

~~~
paulmd
There are mITX/mATX cases that are small/portable and very functional for
water-cooling as well.

I use a Raven RVZ01 (see also FT01 for less aggressive styling) and I have a
120mm AIO in it.

------
Retric
Those Base/Turbo numbers seem off 3.6 / 4.0 GHz (6 core) 3.3 / 4.3 GHz (8
core) while they both are 140W parts.

ED: looks like it's missing the favored core mode which is probably important
for gaming. Which brings up an interesting question if CPU's are now going to
last ~5 years, is buying a 500+$ CPU reasonable?

~~~
jsheard
Intel treats TDP numbers as more of a vague classification than an actual
indication of power consumption. "140W" is basically code for "tons of power".

In PCPerspectives i9-7900X review you can see it uses significantly more power
than the i7-6950X despite them both ostensibly being 140W parts.

[https://www.pcper.com/reviews/Processors/Intel-
Core-i9-7900X...](https://www.pcper.com/reviews/Processors/Intel-
Core-i9-7900X-10-core-Skylake-X-Processor-Review/Power-Perf-Dollar-Conclusi)

~~~
dogma1138
No, Intel classifies TDP as the instantaneous maximum power draw, AMD
classifies it as the average maximum draw over a period of 1M.

~~~
sp332
But jsheard's link shows multiple chips using way over the listed TDP. Here's
a whitepaper from Intel that explains what it means (as of 2011) [PDF]
[https://www.intel.com/content/dam/doc/white-
paper/resources-...](https://www.intel.com/content/dam/doc/white-
paper/resources-xeon-measuring-processor-power-paper.pdf)

 _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._ TCASE is the temperature measured on the
heat spreader over the CPU.

------
myrandomcomment
Eh. Going with AMD for my next home system. Power and cooling is the key for a
home theater + game system.

------
ryao
Why is a 6-core Intel processor beating the more expensive 8-core Ryzen at
video encoding?

~~~
dom0
Higher clocks, much larger thermal envelope, twice as many memory channels,
...

------
jjawssd
Browsers that take advantage of multiple cores more effectively will
accelerate the rate at which Intel circles the drain in consumer applications.

EDIT: why the downvotes? explain yourselves

~~~
wmf
Intel isn't really circling the drain and their future woes are more likely to
be caused by overall shrinking of the PC market, not by loss of market share
to slower chips. As good as Ryzen is, it will probably only increase AMD's
market share from 5% to 10% due to inertia and such.

Speaking of browsers, they aren't really a good benchmark for 6-10 core
processors since anything is going to be fast enough. Also, existing JS can't
really be parallelized so I suspect even a magical browser would still benefit
from single-thread performance.

~~~
ryao
It might be possible to do auto parallelization in some cases like what GCC
can do:

[https://gcc.gnu.org/wiki/AutoParInGCC](https://gcc.gnu.org/wiki/AutoParInGCC)

Still, it might be even better if people would stop writing such JavaScript
intensive websites. They are not very friendly to blind internet users.

------
knorker
Wow. From multiple sites releasing reviews it's clear that an embargo was just
lifted.

And anandtech couldn't bother writing a proper article? Sentence after
sentence just hard to read, with extra commas and just poor sentence
structures. Did they not have time during the embargo?

