so the other day I was shopping for us
state-of-the-art CPU for my gaming and
productivity PC when I realized that
Intel's latest 5820k and 59 30 k both
have six processing cores with
hyper-threading both have 15 Meg's of
cash they have a clock speed difference
of only 6% and yet the difference in
retail price is around $200 woah oh
there's the gotcha
the 5820k only has 28 PCI Express gen3
lanes
you know the electrical connections
behind the slots that we use for
graphics cards and other expansion cards
compared to 40 on the 59 30 K what a
strange way for Intel to differentiate
its mid-tier 20113 cpu from its entry
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learn more let's start with a brief
explanation of what PCI Express or PCIe
lanes are and what they're good for
unlike previous expansion slots like AGP
and PCI PCI Express has a physical size
and an electrical operating mode that
can be independent from each other power
is provided by the pins near the key in
the connector and the rest of the
connector is used or not used to provide
more or less bandwidth to the device
that is plugged into it the more
bandwidth the more lanes are said to be
being used for communication the most
common speeds are 1 X 4 X 8 X + 16 X so
here's a cool fact the different bus
width cards and slots are actually
interoperable that means that installing
a 1 X card in a 16 X slot is fine and
you can even go the other way around in
this video I cut out the back of a
smaller slot and put a larger card into
it all that happens is that both the
slot and the card will now offer
at the speed of the lowest link in the
chain so that's what's gonna happen
if we plug our PCIe 16x graphics card
into what appears to be a 16 X slot but
if the CPU in our system doesn't have
enough PCI Express lanes to provide the
full 16 lanes your motherboard manual
will give you more specifics with a slot
by slot breakdown of how it's going to
work but basically it'll simply
interface with your PC at a lower speed
usually 8x
well that sounds horrible Linus won't
cutting the link speed to my graphics
card in half tank it's performance not
necessarily we're on the third
generation of PCI Express with each new
generation doubling the theoretical
speed of the previous one that means a
modern gen 3 PCIe 16x slot can
communicate four times faster than an
original gen one 16x slot or another way
of thinking about this is that a Gen 3 4
x slot is equivalent to a Gen to 8 X or
a Gen 1 16 X slot but while we already
know that from countless articles that
exist on the topic in the past that no
previous generation of 8 X lot has
bottlenecked a then modern high-end
graphics card with x99s positioning as
the high performance platform of choice
for enthusiasts and for gamers I think
it's fair to say that folks may be
running not just one but two or even
more graphics cards at a time and this
is where concerns start to arise
especially given that AMD and I suspect
also Nvidia is starting to do more
intercardiac spresso n running in
crossfire and again I suspect SLI versus
relying on those dedicated connectors on
the top of the cards so let's introduce
the test to eliminate the variable of a
slightly different clock speed of the
two CPUs and since overclocking K series
chips is so easy these days we're gonna
run both processors at 4 gigahertz a
very conservative overclock that anyone
should be able to attain for the rest of
the bench we've got a gigabyte X 99
gaming 5 4 Way of select compatible
motherboard with 16 gigs of DDR 420 400
megahertz memory from a data thanks to
both of them for providing the hardware
for the test bench we're going to be
using for NVIDIA GeForce GTX 980 for
graphics cards and we're gonna be
running all this off of course 3x 1500
eye power supplies so that nothing melts
during the benchmarking process and here
are the numbers
fraps was used to take average frame
rates for each of our standard test
friends and all games were run at 4k on
pretty demanding settings to ensure that
we were pushing the hardware as hard as
possible as expected a single graphics
card config is not affected in any way
since it's running in 16x mode on either
CPU but dual cards will be running at 8
X 8 X on a 5820k and 16 X 16 X so an
effective doubling on a 59 30 K so I
guess as much as it might be a little
bit more counter intuitive they both ran
the same so there you go
in 3-way SLI both CPUs have to give up
at least one 16x slot but again the
results are not really affected in any
way beyond sort of your standard
variants from one run to another and
then finally in four-way SLI we see oh
actually there's a difference here as
you may or may not have noticed our 28
Lane CPU doesn't have any numbers for
four-way SLI Nvidia requires graphics
cards to be plugged into an 8x slot at
least for SLI certification so only 40
Lane CPUs have support for this
configuration however it should be noted
that even at 4k the benefit of a fourth
card is fairly small and 3-way remains
are recommended max config even if you
feel the need to spend over a thousand
dollars on a bunch of graphics cards to
put in your system it should be noted
that AMD does not have the same
limitation for crossfire so you could
run for graphics cards if you really
wanted to in that case but our
recommendation remains the same anyhow
so that's the story or at least most of
it for gamers anyway compared to the
mainstream z97 platform where it should
be noted that even the highest end CPUs
have a mere 16 lanes Intel's enthusiasts
x99 platform in general and the core i7
5820k cpu in particular is a great
choice even for multi graphics card
gamers if they want to reap the benefits
of an extra two processing cores ddr4
memory and higher overall memory
capacity
limits things do get a little bit dicey
for non-gamers though when it comes to
other PCI expansions so make sure that
you consult the manual of the
motherboard you want before investing in
this particular CPU because you may find
that the MDOT two high-speed storage
slots and in some cases even built on
ports like SATA Express and USB 3
headers might not work with too many PCI
Express cards plugged in or even be
available at all with a 28 Lane CPU so
if in doubt head over to the CPUs and
motherboards section of the Linus tech
tips comm form where our helpful
community will get you sorted out thanks
for watching guys I hope this video put
to rest some of the concerns about oh no
the affordable one doesn't have enough
PCI Express Lanes I hope you all feel a
little bit better I like the video if
you liked it dislike it if you disliked
it leave a comment letting me know did
you learn something today is this
something you already knew was it nice
to have that validated anyway also check
out the link in the video description
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again for watching and as always don't
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