Intel's "12K" Blunder & PCIe Lane x8 v. x16 SLI Benchmark
Intel's "12K" Blunder & PCIe Lane x8 v. x16 SLI Benchmark
2017-06-21
Marvin it's a large part of the
reason that technical media should exist
and part of our job is to filter out
things like the adjectives and the
marketing materials and filter out all
the obfuscation and get to the objective
truth of the matter whatever that may be
Intel's initial marketing that contained
the slide which indicated that the
x-series CPUs would be better for
three-way and four-way SLI or crossfire
configurations for quote 12 K gaming
ignoring the fact that 12 K gaming isn't
really a thing and no one does it or at
least very few people and other things
about 12 K double cat to momentarily the
orange bars on the slide that demarcate
that the case q CPUs like the 7700 K are
not capable of this same task of three
or four-way SLI or multi GPU or more
specifically and more importantly for
this video
the 7700 K and other case cues are not
capable of 12 K gaming where the 7900 X
might be today we're going to be looking
at that and using that as a means or as
a reason that we used to test PCIe Lane
scaling across two cards in SLI talk
about that in a moment and see how the
impact looks for gaming performance
before getting to that this coverage is
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pick up a shirt we'll get to the testing
in a moment but let's start with the 12
K gaming part of the slide this is the
part that needs to point it out
immediately first of all to define a few
things 12 K gaming as Intel defines it
on that slide is probably not what most
people would expect when they hear
something like 12k when you hear 8k we
know that it's scaling 16 by 9 12 K and
Intel's example is actually a bit
different so let's break that down
most commonly 4k means 3840 by 2160
which equals 8.3 million pixel then
there's a 5k which is 50 120 by 2880
resolution and 14 point 7 million pixels
or 14 point 7 megapixels
we next go up to 8k resolution
seventy six eighty by forty three twenty
or thirty three point two million pixels
thirty three megapixels so what is
twelve K well based on this scaling we
would expect twelve K to be something
like eleven thousand five hundred and
twenty pixels by something like sixty
four eighty pixels using a 16 by 9
aspect ratio that puts us at seventy
five million pixels or seventy five mega
pixels that's more than two times the
pixel count of 8k and that's a big deal
if you could play twelve K games it
would be pretty remarkable technically
speaking twelve K is not officially
defined I'm not presently aware of any
displays in the consumer market which
are twelve K ready but either way it's
not what it sounds like when we look at
Intel's version Intel doesn't mean
seventy five million pixels Intel means
twenty five million pixels at a
resolution of eleven thousand five
hundred twenty pixels of by 2160 or
three at 4k displays next to each other
what we would probably call triple Forte
we emailed the companies to confirm this
and that's what they said they said it
is three 4k displays next to each other
which they are calling or abbreviating
twelve K that's a three times difference
in pixel count from what the consumers
expectation might be of twelve K and
what the actual meaning is behind
Intel's marketing but even then that's
not really the part that matters
regardless of some of Intel's
embarrassing marketing for this launch
like extreme mega tasking the part that
matters is that they're claiming a
higher resolution performs better on
other CPUs even with PCIe Lane scaling
this is still largely a marketing stunt
here's why this is a GPU benchmark now
just like when AMD claimed great 4k
performance on Rison despite the fact
that the GPU actually basically does all
the work at that point and that it's
completely irrelevant as a rallying
point for CPU Intel is now piling on and
claiming that triple 4k performance is
because of the x-series CPUs that just
came out in reality the only reason this
would ever matter is because of the lane
count difference which of course has
been a major topic of discussion lately
so then this is basically becoming a
PCIe scalability test between multiple
GPU configurations in this case 2-way
SLI with 1080p is and we're going with
two-way SLI
because although Intel's slide and
technical marketing team indicate a
threeway or four-way SLI compatibility
for multi-gpu the fact of the matter is
that nvidia does not support 3-way or
four-way SLI for gaming it's physically
impossible to do it so with Pascal
that's the that's the reality the only
way you could do 3-way or four-way with
a relevant card at this point would be
to do something with either AMD or with
the Maxwell series in which case even
three 980ti s would not equate the power
of two 1080 Ti so you really might as
well just do this and as for an these
cards you've basically got rx5 ATS right
now Vega is not out and so from that
perspective you'd have to pile on three
or four or five ATS to come close to
doing what two of these could do that's
not the down talk to 580 but this really
isn't what it's meant to compete with so
what you end up with is something where
there's a very specific use case where
this test can make sense and then the
rest of them that would actually draw
all those PCIe lanes Intel's talking
about just don't work anymore doesn't
work with Pascal and there's no point in
doing it with the rx5 ATS maybe with
Vega but that doesn't exist today on the
market so we can't quite test that just
yet Intel does have a point that the
lane count of some of the x-series CPUs
is significantly higher than the lane
count of the previous case cue CPUs but
they also indicate on the slide that the
6 to 18 core parts are the only one that
the statement applies to which means
that the KB Lake X parts need not apply
and that said the six core eight core
parts as Paul has been saying quite
frequently on his channel actually have
twenty eight lanes sure that's still
better than 16 on the 7700 K but that
still doesn't get you to 2 by 16 cards
anyway we emailed Intel about the fact
that three-way and four-way SLI and
Pascal is not possible for gaming and as
if the company would like to respond for
this video Intel's official statement to
gamers Nexus is the following the 12 K
gaming mentioned in the table from our
product briefing info for press included
an error referring to an older PC gaming
GPU configuration the x-series platform
enables true PCIe by 16 + by 16
configure
nations whether or not it performs
better is dependent on the software and
the graphics vendor so having gotten
through the marketing screw-up and
Intel's statement to us what we're left
with is actually a really cool testing
opportunity for PCIe Lane scaling on two
different CPUs we did this before with
the same cpu where we used motherboard
BIOS to basically toggle by eight verses
by sixteen land but now we're testing it
with the 7900 x-rays of the 7700 k
specifically to verify intel's marketing
claims and then hopefully as collateral
to that you'll get a benefit in figuring
out if doing something like 210 ATT is
is actually worth it on either one of
these platforms with regard to lane
availability so with the 7900 a
configuration we're doing a few things
one we're running at stock in some of
the tests and we're also doing a
configuration where we've overclocked it
to equate the 7700 k a stock cpu clock
speed to 4.5 gigahertz and we've also
disabled 12 of the threads leaving it
with 8 that puts that basically a 7700 k
so for those tests we're looking at more
of a direct comparison core to core
clock the clock of PCIe Lane bandwidth
differences between the two platforms
where one can peel off 32 lanes to the
two GPUs and the other one is peeling
off 16 in 8 and 8 or in the former 16
and 16 anyway let's get to the testing
remember the scope is that Intel is
saying a 7700 K isn't rated for triple
4k or what they erroneously called 12 K
and it's saying that the x-series is
better for it
the implication is a better PCIe Lane
performance as marked by the orange bars
on their slide last time we did a PCIe
SLI scaling test we saw less than 1%
difference this time we're being a lot
more judicious with a minimum run count
of 5 test passes per test collecting a
standard deviation as well and having
spoken with Nvidia and sis about test
scenarios that would most likely show a
PCIe scaling difference so that we can
really put this thing to the test rather
than testing 30 some-odd games and
really finding out that doesn't do
anything it turns out even in the best
possible light none of it matters and
well there's one exception but we'll get
to that now one problem here we don't
have three 4k monitors to test
and if we did we wouldn't have space
with it but there's an important thing
here with this type of testing all that
really matters is the pixel count so
three 4k monitors would give you a pixel
count of twenty four million eight
hundred eighty three thousand two
hundred pixels and using our rarely used
resolution that we found we are on 66 51
by 3741 so that gives us 24 million
eight hundred eighty one thousand three
hundred ninety one pixels you subtract
that from the first and end up with an
1809 pixel difference really not bad
that is so insignificant that we can
basically call these resolutions the
same and carry on with our testing and
one more note here we're using DSR to
achieve these resolutions in the past
we've tested DSR scaling and its impact
on performance or the performance hit to
do the scaling and in that testing along
with more recent testing for this we see
a scaling of about one to three percent
so there's really not a big difference
in a way that would make this different
in a meaningful fashion from if you
actually had a monitor at this
resolution or three 4k monitors at this
pixel count so that's what we're working
with we've got a 1 to 3% tag from DSR
but it applies equally to all of the
tests so basically doesn't exist for the
purpose of this testing and other than
that we're working with 66 51 by 37 41
now for the final testing information a
couple more important things one
multi-gpu is really hard to find modern
games that actually scale well with i
we've tried it in recent history and the
options are basically sniper elite and
maybe one or two other games really not
that many sniper lis is kind of the
seminal example so that's the first
thing just because there might be
scaling in the games we're using here
doesn't mean you should expect multi-gpu
to actually be worth it in anything you
do IRL outside of a testing environment
the next thing these things that in the
past have tended to stress PCI interface
limitations the most have been synthetic
test that's fire strike with custom tune
settings to really blast the GPUs now
times by now superposition and then we
can also look at something like ashes of
the singularity which is for all intents
and purposes
synthetic and we've also got a couple of
games in here as well that have been
proven to generally show good SLI
scaling or PCIe Lane testing in the past
one of them Crysis 3 it's a bit old but
it works really well for this purpose
and then the other Sniper Elite 4 which
has nearly 2 X K lean on multi-gpu that
is the best we can get for getting both
of these things to pump out data to
their maximum potential basically I've
got a couple other games in there as
well but for full testing methodology
check the link in the description below
and then for tests where we've got the
7900 X with cores and threads disables
going to clock boosted that's basically
to eliminate the final variable which is
this thing has more threads and a
different clock so that's why that's
done with fire strike configured it to
fire strike ultra with a custom 6651 by
3741 resolution which we are going to
call 25 mega pixel resolution from here
on out because it's easier we're seeing
the I 970 900 X CPU and dual 1080 TI f
tws operate with graphics cores of 27.4
and 15 point seven four one and two
compared to these 7700 K scores of 26.9
six and 15.3 for this data was collected
over five test passes each producing a
margin of variance of plus or minus 0.1
FPS not percent just 0.1 FPS resolution
on these tests that's pretty accurate so
we're looking at a performance
difference in the range of 1 to 2% max
we could somewhat confidently state that
the extra eight lanes account for this
but frankly the 8 thread 4.5 gigahertz
version of the 7900 X helps us find out
that that's not necessarily the case
this runs framerate closer to the 7700 K
and averages out to 26.5 3 FPS for
graphics 1 1501 for graphics 2 once
we've controlled 2 threads and speeds
even that 1 to 2% window pretty much
goes away is now within test to test
variants the graphics core differences
come down to 45 97 verses 44 97 if you
care 100 point difference which is again
accounted for by less than 1 FPS /
graphics 1 and less than 0.5 FPS for
graphics - but what if we made the test
easier let's go down to firestrike ultra
at 4k just because now by eliminating an
awful load from the GPU to allow the CPU
to start showing a difference we see
scaling up a couple frames the
difference is about three FPS on
graphics one was the 7900 X on the lead
and about three to four FPS on graphics
- but again at this point we can no
longer confidently state a difference
caused by PCIe lanes disabling threads
and normalizing for speed helps with
that a bit we see the eight thread 700 X
running a 75048 fps graphics one score
and 48.1 fps graphics to score that
brings us to about a two percent
difference in graphics one at this point
it looks like that could be an advantage
of the extra lanes we're not fully
confident because it is pretty close but
it does look that way in this particular
test time spy doesn't have a twenty five
megapixel configuration that we could
run so we ran to that 4k this one posts
an FPS difference of about 2.3 FPS for
gravity's won the sony 900 x leading and
about 1.6 ft s for graphics 2
respectively the percent scaling yields
an increase in performance of 2.9
percent and 2.8 percent for the 7900 x
this difference again starts to hinge
more on the cpus at 4k than on the lanes
so let's increase the resolution and
load on the GPUs again just to really
stress the PCIe interface for using
Unigine super position now and it
doesn't have a 25 mega pixel setting
either but it does have 8 K which is a
higher pixel count of 33 megapixels
versus 25 of triple 4k we're seeing an
average FPS across 5 runs of 30.8 9
versus 39 5 technically favoring the
7700 K this difference is within our
test variance with our margin of error
calculating out to plus or minus 0.25
FPS again basically equal even the
minimums output by the software are
close and we don't normally like
minimums but the maximums are also
nearly equal and the score if you're
curious comes out to 41 29.5 on the
center 900 X vs. 4138 I'm a 7700 K
within variance of test the test passes
they are the same the PCIe Lane
advantage isn't helping and the X series
isn't magically better at this non
tenable 8k resolution
let's get back to that 25 mega pixel
number again by using games with Crysis
3 which is old but still one of the best
graphics benchmarking tools available
for PCIe Lane scalability we're seeing a
difference of about 1 FPS average our
test variance here is
0.76 FPS which is most of one FPS so
that means our CPUs are again
effectively equal we cannot confidently
declare that one is better than the
other which means that we cannot
confidently declare if there's a
difference because of the PCIe lane and
of course because everyone just looks at
the charts to claim a victory going to
say the 7500 K is faster that might be
true if you were to analyze it really
heavily and do a whole bunch more test
passes but as it stands now we must
abide by the confines of our numbers and
those say that the two CPUs are equal in
their respective configurations with
ashes of the singularity at 25 mega
pixels and extreme settings using 8 tap
msaa and DirectX 12 we see that the game
stresses the GPS to a point of running
at around 40 fps honestly that's still
fairly impressive performance overall
given the resolution but then again it's
a synthetic benchmark both regards to
scaling performance it's not a huge
difference that we are seeing more of
one than we saw in the other titles this
is a DirectX 12 bench so that could
account for some of the differences the
7700 K runs at 39.9 fps averaged 13.5 1%
blows 11.9 FPS 0 or some blows compared
to the 4 core 8 thread 7900 X variant
which starts at 42 FPS average we're
looking at a performance increase with
the extra lanes of about 5 to 6 percent
the 7900 X without it's overclock does
better in frame time variants consistent
with our upcoming Sniper Elite results
next sniper 4 is another special kind of
game we had ashes of the singularity
which has done built very heavily for
benchmarking purposes and so means that
it is optimized for Hardware Sniper
Elite 4 is also optimized for hardware
in our recent multi-gpu benchmarks we
showed about a 100% scaling with
crossfire 5 ATS and Sniper Elite only
very few modern games managed this feat
with this game we're seen scaling up
about 100 percent even with DX 11 which
was used because Nvidia's cards seemed
to put more load on the PCIe bus when
using the X 11 even with all of this
going for it with all that utilization
of both GPUs we're seeing Sniper Elite
for roughly tied between tests the 7700
K runs at about 54 FPS average of 49 and
42 fps
those the average was 54 FPS every
single pass so that's consistent and the
lows have a plus or minus error of about
1.7 FPS the 7900 x8 thread CPU ran about
53 to 54 FPS average with a range plus
or minus 0.3 FPS and lows at 42 and 35
with the range of 0.5 and 1.7
respectively
some of this difference can be chalked
up to our increased voltage and the
overclock with regard to the low
performance the frame times which
sometimes show a PHA and time variance
change because you're overclocking and
over voltage so things can happen the
non overclocked 7900 X was more stable
though at 55 FPS 48 fps and 42 FPS
respectively averaged at 1% in point one
percent finally total war Warhammer
helps us get a wider spread of game
variety but ultimately also failed to
produce any meaningful differences the
7700 K runs an average FPS of around 36
here with lows at 21 and 20 the 7900 X
manages 37 FPS average but it has too
many other variables at play so we can
lock it down increasing the clock speed
in to say when 12 threads makes for a
better test putting us at about 38 FPS
average the clock speed matters more
than cores in this game but it's clear
that the CPU is still at play here we
cannot confidently state an advantage
from PCIe lanes alone in this test if
there is one it's in the range of 3 to
5% or there abouts
and would vanish the moments you
decrease load on the GPUs and increase
load on the CPUs so looking at all these
there's really mostly no difference in
terms of performance from PCIe lanes and
scaling them but we did see 5 to 6%
scaling and ashes of the singularity
with DirectX 12 and 3 to 5 ish 5.5 with
total war Warhammer there's no real
scaling to speak of in Sniper none
really in crisis and the synthetic spin
seems much care either even if you're
going to play triple 4k or do some kind
of very high resolution monitor 8k maybe
at the end of the day you're not going
to torture it the way we are we're
putting these things through ultra
settings 8 1/2 MSAA which just seems
wholly unnecessary for this kind of
resolution and trying to put as much
load on the PCIe bus as possible it is
our intention to stress the PCIe bus
what happens though if you back off of
that well if you scale back and you
lower the load on the GPU is you end up
coming back to the CPU and loading it so
at that point we're looking at something
that would level out and completely
nullify for the most part any actual
PCIe lane differences that you might
encounter regarding PCIe lanes for GPUs
the concern seems a little blown out of
proportion however there is still a
concern for PCIe lanes in general on
these CPUs because one it be a hell of a
lot easier to understand what's going on
what's supported between platforms and
CPUs if they were either all the same or
just had more lanes and two you still
need to be cautious about what you're
buying with regard to high-speed i/o
devices how many you're using and
whether or not you care about going
through the DMI versus just talking to
the cpu directly so all of that matters
as well but it looks like with our
testing the GPU performance isn't quite
as big of a deal as some of the other
stuff is with this platform and there
are plenty of other problems the biggest
thing here is that Intel is damaging its
brand credibility by making claims like
12k gaming pointing at three and four
Way SLI as a reason which is not really
possible again and we end up looking at
the same performance as the Saudis have
100k for the most part ultimately even
with all of those caveats none of this
matters because multi-gpu scaling is so
rare anyway we I don't think have ever
recommended it in all the years of
working with SLI and crossfire I don't
think either one has gotten her
recommendation there are specific
instances where you would do multi-gpu
maybe like production where you're just
going to run blender and task you're
rendering to each card in which case it
doesn't care about SLI or maybe you have
a very specific use case for gaming and
you've already purchased the best card
in terms of raw performance on the
market whether that's a Titan X or a
1080i or maybe in the future some Vega
variant if you buy one of those maybe
multi-gpu make sense because you have
nowhere else to go above you but for the
most part this is something that is a
really limited use case the scaling does
not look like it matters in a lot of
instances but quoting our Nvidia
industry
contacts you'd really have to test
30-plus titles to get a full spread and
truly understand what it looks like
across everything on the market but for
games that do actually scale with SLI
and scale well its hit and miss with
mostly miss especially on the synthetics
which often do stress things the most
for PCIe so that's all for this one if
you'd like to help us with this type of
testing is always good at patreon.com
slash gamers Nexus or you can subscribe
for more information thank you for
watching I'll see you all next time
you
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