$300 CPU Beats $4000 CPU?? - Cores vs clockspeed for video encoding
$300 CPU Beats $4000 CPU?? - Cores vs clockspeed for video encoding
2016-09-13
okay do you remember that project I was
working on where for the better part of
six months I built up this badass 36
core dual Xeon server machine to handle
our video encoding and transcoding tasks
over the network here well fast-forward
almost a year and many many hours spent
on diagnosis not to mention a kick in
the right direction from this post over
on Puget systems I think I finally
figured out why we never got quite the
performance that I expected is it
possible then that a four thousand
dollar twenty two core CPU could be
outperformed by one that costs only a
few hundred bucks for video encoding is
it possible that I made a mistake
nothing to hold on to
fails all I read in the sign I'm
definitely getting their attention so
does one of the recurring themes of
these laptop or bus videos become -
failure montages and I mean aside from
those ones let's find out
freshbooks is the super simple invoicing
solution that lets you get organized
save time and get paid faster click now
at the link in the video description to
try it for free ok so to open this video
up we need to take a closer than usual
look at my test bench i wanted to
eliminate bottlenecks wherever possible
so that the cpu is the only factor in my
performance evaluation so for that
reason most of the performance testing
was done on an Intel 750 series 1.2
terabyte nvme SSD a gtx titan X 128 gigs
of DDR 4 quad channel memory on an X 99
deluxe 2 motherboard and the CPUs tested
are as follows intel's top of the server
line $26.99 v4 22 cores e on their top
of the high-end desktop line 10 core
Core i7 extreme 69 50 X the 8 core and 6
core 6900 K and 6800 K and finally I
decided to throw in their flagship
mainstream 6700 K quad core to give us
the most complete picture possible at
the end of the day as for the video
tests I apologize in advance if the
codec or encoder application that you
personally prefer wasn't covered but
this was done as much to optimize the
linus media group workflow as it was for
the purposes of creating a video so i'm
looking at four different scenarios that
we encounter pretty much daily 1
transcoding a 4k mxf off of our sony FS
5 to 1080p sinha form our mezzanine
codec of choice for editing to exporting
a finished project in this case a
green-screen episode of fast as possible
directly to h.264 for publication to
youtube 3 a quick export in cinah form
how we normally export so that a network
media encoder machine with a watch
folder can transcode it to h.264 and
automatically upload it to the channel
and for finally the performance of that
Sinha form to h.264 conversion with the
1080p to 4k up sampling that we perform
for the reasons we covered more
thoroughly in this video here so I ran
every test with and without CUDA
acceleration enabled in Adobe Media
encoder and used a second machine to
capture the screen output with CPU and
GPU usage displayed so I could review it
later let's begin then with scenario 1
this is what most people probably expect
from a multi-core CPU in a video
encoding benchmark traditionally this is
one of the easiest workloads to scale
across more course and our CPU usage
graph indicates that all is working
beautifully
throwing a GPU into the mix levels the
playing field somewhat but this won't
surprise anyone who knows how deep you
dependent of video codecs Sena form is
and how that bastard law of diminishing
returns works moving on to exporting a
project directly from our Sena form
timeline in CPU only mode we see nice
scaling with more cores but maybe not
quite the dominance we'd expect from a
chip with and yes I know it doesn't
quite work this way like 60 gigahertz of
theoretical total performance this is a
hint of things to come and been throwing
a GPU into the mix paints a much more
extreme picture here the CUDA
accelerated code path not only reaps
very little benefit from more than 6
course it punishes CPUs with lower clock
speeds in a way that I really didn't
expect observed GPU usage is much lower
than any other processor in this test
for our four thousand dollar chip and
the CPU usage we see of about 25% tells
us this is not a heavily threaded
workload oops
alright so let's break that down then
into the individual steps and find out
where our heavy multi-thousand dollar
investment in an uber xeon falls apart
exporting the project from a center form
1080p timeline to a Sena form 1080p file
theoretically elsewhere on the network
but I'm using my nvme drive as a target
for these benchmarks for consistency
sake is pretty flat across the board and
curiously this is true with or without
CUDA acceleration enabled in media
encoder GPU usage is 85% regardless of
which drop-down so this is clearly
nearly 100% GPU dependent which leads us
then to the second step in the process
converting from Sena form 1080 to h.264
4k in CPU mode only we see a similar
trend to our initial ingest test more
horses is better but only to a point
then in GPU assisted mode there it is
we are almost entirely bound by per core
performance with a lowly quad-core
costing one tenth as much handily
beating our xeon beast so then did i
horribly miss configure our video
encoding ingest stations and output
server are Zeon's basically pointless in
video work well if you're looking simply
at the graphs i just showed you
along with these charts of approximate
CPU and GPU usage in all the different
scenarios i tested then it's pretty
clear that these lower clocked many-core
chips are being underutilized and the
money though i fortunately didn't pay
for them would be better invested almost
anywhere else but as always the real
world isn't really that simple and it's
going to come down to the needs and
workflow of each individual or
organization virtualization can be used
to get damn near 100% scaling out of as
many cores as you please
encoding software like Sorenson squeeze
can process many files at a time and on
the subject of different software
testing any given codec in any given
software could yield very different
results from what you're looking at here
so there's no way around testing just
make sure that when you do so for
yourself you go in without any
assumptions about what the right tool
for the job will end up being so you can
avoid pulling a Linus speaking of tools
for the job
it's summer apparently
something-something boarding planes
trains driving
a car leave your worries behind okay I
don't know what any of that stuff in my
notes is but today's sponsor is tunnel
bear and if today's lack of online
privacy brings out your inner grizzly
bear rawr rawr then you can try Tunnel
bear it's simple and it is free to try
at the link in the video description
it's the easy to use VPN that makes it
so you can browse privately and enjoy a
more open Internet without all that
hassle associated with more complex VPN
solutions any you know port forwarding
your DNS or any nonsense like that you
just click the button and boom you can
tunnel in to up to 20 different
countries and it will appear to the
websites and services that you are using
as though you are coming from that
country and Tunnel bear has a top rated
privacy policy and does not log your
activity so try it free with 500
megabytes and no credit card required
and if you decide you like it and you
want to get a year of unlimited data you
can save 10% by going to tunnel bear
comm slash LTT linked in the video
description so thanks for watching guys
if this video sucked you know what to do
but if it was awesome get subscribed hit
that like button or even check out the
link to where to buy the stuff we
featured and Amazon in the video
description also linked in the
description is our merch store which has
cool t-shirts just like this one and our
community forum which you should totally
join now that you're done doing all that
stuff you're probably wondering what to
watch next so check out that little
button on the top right to check out our
latest video over on channel super fun
We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.