usb4 is an absolute Game Changer we're
talking 40 gigabit per second data rates support for 8K displays and external
gpus a single cable docking at up to 240
watt charging rates and all over the
same USB type-c connectors and cables that you have come to know into yes what
actually usb4 is more like a collection
of optional standards okay it sounds like what you're talking about is USB 4
gen 3x2 with some of those optional
features implemented so your sponsor origin pz would probably want you to
clarify that so pedantic Riley is very annoying but he's
also right I mean it shouldn't surprise me coming from the same industry
Consortium that brought us naming like USB 3.2 gen 2x2 but five years after
Intel's announcement that they would open source Thunderbolt USB 4 is finally
out in force and has turned out to be one of the most confusing standards ever
to make it onto a consumer PC the good news though is that by the time we're
finished here you will understand both its pros and cons and how it operates or
doesn't with other standards like Thunderbolt including real world
examples
the simple explanation really is that
usb4 is an open version of Thunderbolt 3
based on the specifications the Intel released back in 2017. there is a lot to
love about this move for one thing it frees vendors from the shackles of
Intel's notoriously onerous certification process and for another it
allows non-Intel CPU manufacturers like
apple or especially AMD who didn't co-develop the standard to support
features that used to be Thunderbolt exclusive like 40 gigabit data rates
daisy chaining together multiple devices and PCIe tunneling which is super cool
and allows you to turn your USBC Port into a PCI Express connection for
devices like external gpus and other add-on cards the problem is that when
you free the notoriously Cheapskate computer industry from compliance
programs you invite shortcuts and usb4
invites a lot of shortcuts in no
particular order here are the optional components of the spec that can be left
off of your device while still allowing the vendor to slap usb4 on the spec
sheet 40 gigabit transfer rates 20
gigabit USB 3.2 Thunderbolt alternate
mode USBC alternate mode and yes PCIe
tunneling yeah in a world where almost
nothing you can connect to a laptop needs the speed of even a last gen USB
320 gig Port isn't the whole point of usb4 PCIe tunneling and interoperability
with Thunderbolt 3 devices well Microsoft sure thought so which is
why they actually require external usb4
ports on Windows 11 devices to support PCIe tunneling which theoretically
ensures backwards compatibility with Thunderbolt 3 devices but there is no
such guarantee if you were to buy a bare motherboard or a non-Windows device and
from my conversations with a device maker whose previous Thunderbolt 3
notebook actually never ended up getting certified by Intel there is a lot more
to this interoperability than just checking a box for PCIe tunneling making
matters even more confusing Microsoft does not appear to have mandates in
place for any of the other features the good news is that when it works it works
really well here is a small bushel of Thunderbolt 3 Thunderbolt 4 and USB 4
devices that we've tried on the Voyager a1600 gaming and content creation laptop
that Corsair provided for this video and I'm going to show you guys what the
experience is like on a usb4 laptop after the short message from our sponsor
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system's look monitor performance and manage your Corsair devices so you can
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PC gaming or content Creation in a super compact package visit the link down
below to learn more for our first trick we'll be trying to connect a couple of
Thunderbolt 3 devices to our USB 4 laptop and the reason this matters is
because these older devices would have been designed at a time that usb4
compatibility wouldn't have been a consideration so if they work it means
that usb4 is transparently compatible
with Thunderbolt 3 at least okay this
one works for these particular devices now that first one I plugged in using a
usb4 cable and the second one we're
going to try an older Thunderbolt 3 cable
we got it there it is Cal digit 10 gig
network adapter this backwards compatibility means that any Thunderbolt
3 device and USB 4 system should work
with each other now I would expect to find some edge cases particularly with
very old devices due to Intel specific handshakes that used to be required but
we didn't run into any of them while we were working on this video now let's try
a Thunderbolt 4 device in the interest of giving ourselves our best shot here
we're going to go ahead and use a Thunderbolt 4 validated cable look at
that easy and we don't even need that old
Intel application for managing all of our connected devices I mean I expected
this to work the main difference between Thunderbolt 3 and Thunderbolt 4 is
actually also in enforcement of compliance so Thunderbolt 4 requires in
order to get the Intel badge support for two 4K displays or a single 8K display
computers must have 32 gigabit per second of PCIe bandwidth this is to
address the issues folks would have with high bandwidth devices on some
Thunderbolt 3 laptops particularly e-gpus and they must support security
improvements that protect your device from malicious connected devices
plugable.com actually has a great write-up on the differences between
Thunderbolt 3 and Thunderbolt 4. what about speed though in an attempt to
crack over 20 gigabit per second of transfers we are using three separate
ssds and our Network share and copying
all to our boot drive at the same time three more six gigabytes a second yes
can confirm that we are not limited to 20 gigabit per second even though that
could be the case with usb4 wow those
transfers are almost all done that's really impressive those were 22 Gigabyte
files mind-blowing and the most mind-blowing thing is that aside from
some Cal digit devices that took a little while to be detected we didn't
run into any issues using Thunderbolt devices on this laptop and those Cal
digit ones they were actually just downloading drivers in the background
wow but there is definitely more to know
here we tested a lot of configurations and discovered not only some differences
between Thunderbolt and usb4 but also
between Apple's implementation and the one we found on the Corsair Voyager see
on a Mac two Cinema 5K displays this
would work just connect them to any Thunderbolt Port you want and it works
as expected however when we attempt to do the same thing with the Voyager
either only one display works or if we
go through a hub we can run both of them but they're limited to 4K resolution
unless we actually unplug them from our
Thunderbolt ports plug one into Thunderbolt and one into the regular
USBC 3.2 Port over on the other side
both running at 5K the reason for this
is quite interesting in the verges coverage of this laptop Corsair senior
Public Relations Specialist Justin oakbina revealed that the USB 4 ports
are hooked up to the CPU for display meanwhile the 3.2 ports are hooked up to
the GPU so they might look the same but
because they're running DisplayPort alt mode they're limited to the capabilities
of whichever GPU is physically attached
to them so we're able to run more than one 5K display by connecting to each of
those gpus separately this is another really interesting
example of different protocols behaving in different ways even if they go over
the same connectors now alt mode what we're talking about here uses a physical
chip connected to the USB port to send a
signal down that differs from standard USB tunneling is not the same it
converts the DisplayPort signal to packets that can be sent along a USB
connection allowing for things like data and PCIe tunnel packets to be sent
alongside so your mileage may vary depending on whether your machine uses
alt mode or tunneled DisplayPort in poor
Tanner if only Apple could have provided a
display with an actual stand okay you're good you're unplugged yeah he's got the
tracksuit and everything okay thank you let's try some older more obscure stuff
like this akitio dual Drive Dock and uh
how about this Thunderbolt archival tape
backup system I remember the tape drive actually requiring special software so
it's possible this hard drive will show up even if the tape drive wouldn't oh
hey there we go look at that that's awesome all right goodbye monitor
external drive and there they are that's wild I mean it
shouldn't surprise me that much given that usb4 is supposed to be based on the
Thunderbolt spec and therefore should be the same thing but you just don't expect
heck to work that well right out of the gate and there were some things that led
me to believe that maybe they weren't quite the same for example Thunderbolt
has supported multiple Thunderbolt devices Daisy chained together since the
beginning but the Wikipedia page for usb4 explicitly says that such daisy
chaining is not supported to clarify you could totally plug a Thunderbolt Hub
into your usb4 laptop and then a USB hub
into that and another one into that and so on and so forth until the signal
timing becomes an issue but Intel seems to believe that connecting additional
PCIe tunneling devices Downstream well
that's their jam so what happens if we try it I guess
we've already got this guy right here so instead of plugging our additional
drives into the laptop directly why don't we daisy chain I see the hard
drive in here so but there they are the ssds in here have shown up but how far
can we go uh why don't we do a hub
right oh yeah I don't know if we have to go all the
way to six but Let's do let's do one more at least here here comes another
one there they are it's all showing up I
want one more I want my 10 gig Ethernet
say cool
oh I like that one we got it working with
anywhere from two to three devices pretty consistently but as you can see
your mileage may vary though this is
unlikely to ever affect you many newer Thunderbolt devices expect the hubs and
docs have controllers in them that can communicate either using Thunderbolt
like PCIe tunneling protocols or traditional USB protocols so in many
cases it won't necessarily be obvious to you until you try to plug in another
Downstream device which protocol your device is using now rather than trying
to run all five of these devices let's go for a single really demanding one an
external GPU here we go oh fan spinning that's a good sign there
it is our RTX 2070 external GPU not that
we'll need to upgrade the GPU anytime soon given that this laptop has a Radeon
6800 in it already anyway but the point is that it does work and the a1600 does
all of this partly thanks to AMD's inclusion of usb4 on their Zen 3 plus
ryzen 7000 processors but in the absence
of Intel standards compliance team it's also thanks to the way that Corsair has
worked with their OEM to internally validate their implementation however
watch how easily I can break things
whoops here's what happened there while
Thunderbolt has used the same USBC connector as USB devices for half a
decade now the Thunderbolt protocol which you've heard me refer to a few
times and it's kind of like the language that's actually being spoken over the
cable well it's closer to PCI Express
than it is to USB so this along with its
traditionally much higher data rates means that it has far less tolerance for
latency and inconsistency which means that cable quality matters a lot it's
not all that like here uh oh this anchor
cable is one that I specifically pulled aside for this this is pretty cool
because this cable is older than the usb4 spec it's just a high quality C2C
cable and give it a second
oh wait did that not work actually tried it on a different
Thunderbolt only device this network adapter
and on the network adapter it totally
works in spite of this thing not having a USB operating mode that's wild let's
try this usb4 type c cable one that is
actually a newer validated one and see if the external GPU picks up that one no
as you can see standard USBC cables
might work fine even with Thunderbolt only devices but only the ones with the
built-in signal stabilizer like this one are actually guaranteed to work with
Thunderbolt devices and that's going to be true for any connection using that
PCIe based Thunderbolt protocol regardless of whether it's on an Intel
certified Thunderbolt device or a USB 4
device this is why USB 4 is only rated
at 40 gigabit per second over a one meter cable while Thunderbolt 4 is rated
at that same speed at up to 2 meters to
my knowledge there are no non in tell Thunderbolt usb4 signal stabilized cable
products and curiously this is another
really interesting one this active Thunderbolt 3 cable from Corning didn't
work on any of our devices on our usb4
laptop here hold on I can just demonstrate this real quick there we go
yeah no dice which means that our days
of Hit or Miss cable compatibility are not over even if they are a lot better
to answer the question then is usb4
compatible with Thunderbolt 3 and 4 devices the answer is yes
but also no the level of compatibility
really is going to come down to how good of an implementation you get the Corsair
Voyager a 1600 performed admirably but
it's a machine that implements far better than the bare minimum spec and
one that doesn't go this far may not be as smooth and as we saw today your
mileage may vary when it comes to unofficial features like daisy chaining
and support for specialty cables like these Optical ones from Corning the big
question this phrases then is why did the usbif allow half-baked usb4 at all
well it seems to come down to phones mobile devices could get some very valid
benefits from usb4 like higher data rates and DisplayPort tunneling for
external devices with Samsung Dex or whatever but they're unlikely to need
the PCIe tunneling that Thunderbolt is known for or daisy chaining and the like
they're also unlikely to need this segue
to our sponsor that I'm known for because we already told you it's sponsored by Corsair if you guys enjoyed
this video and you're looking to learn more about Thunderbolt this video on ShortCircuit shows off my very favorite
Thunderbolt 4 dock it's actually uh this one freaking awesome two and a half kick
land