Radeon Vega: FE Vcore Behemoth - VRM & PCB Analysis
Radeon Vega: FE Vcore Behemoth - VRM & PCB Analysis
2017-07-02
hey guys build good here and today we're
going to be taking a look at the Vega
frontier edition PCV and this thing
packs the most powerful V core vrm I
have ever seen on a reference card so
we'll just start right off with that
before that this coverage is brought to
you by the core g21 enclosure from
thermal take a $70 case with two four
millimeters thick tempered glass side
panels mesh ventilation in the front for
breathability a rarity in cases these
days and a power supply shroud with top
mounted SSD sleds learn more at the link
in the description below the VMO
monstrosity is this giant l-shaped block
around the card around the court and
this L shape is actually like it looks
really weird because we've never seen as
far as I know I've never seen this on a
another card but this actually is the
optimum vrm layout for any scenario
obviously it isn't very popular on GPUs
because generally you don't want your
GPU being you know really really tall
but the reason why this is the optimal
layout and why I am be used it is
basically the distance from any of your
actual phases to the GPU core because
that's what it's powering this brick
right here that's the GPU core these two
down here are the HBM sacks but this vrm
is pumping current into this block right
here and so the closer it can be to that
the less voltage drop you suffer which
ever so slightly improves your
efficiency and it also slightly improves
voltage regulation because you have less
propagation delay from basically the
core to the VRM so this does have
benefits they are very very minor though
that's why it's you know it's like it
doesn't matter a ton really the really
user to hit diminishing returns on like
high-end cards where they have the
massive power planes going through the
of through the PCB anyway where this
would be more like where you'd really
start seeing a difference is when you
have vrm layouts which are really unab
simal right like this might be the
optimal layout but the difference
between this and something less than
ideal is not that bad
well less than this is not that bad the
difference between well cars where
you'll see this actually be a major
problem is dual GPU cards because
they're the you basically end up with a
situation where having massive power
planes is just not an option because you
need to fix so much stuff on those cards
that you actually see voltage drop a cup
from the vrm to the GPU core you know as
high as fifty to even a hundred
millivolts under load which is crazy so
like your erm will be be putting out 1.3
volts by the time it hits the GPU core
you're only getting 1.2 here you'll
basically have like this phase right
here would fit at 1.2 and by the time it
gets to the GPU core you'd be at like
1.19 alright oops one too many ones but
you'd be at like one point one nine
volts so this is definitely like the
perfect play how forever erm but it
won't really like you know it's cool
that it that AMD opposite for it it's
cool that it's possible thanks to the
HBM ultimately it won't probably matter
that much but I did feel like pointing
it out since it does explain why am he
actually sort of went for this l-shaped
because you know it's like why wouldn't
they just use all of this empty space
over here well they put the fan over
there and this layout is actually just
straight-up better than trying to put
you know multiple than trying to cram a
16 phase DRM into this area so yeah
that's kind of cool now let's talk
actual details on on this erm why it's
so powerful not you know funky layout
obviously doesn't mean it's capable it's
a one two three four five six seven
eight nine ten eleven twelve phase vrm
design so naturally it's obviously
running a doubling scheme as you can't
buy a twelve phase voltage controller
which we need to go on the back of the
card to check that out
the voltage controller is this chip
right over here and that is a eye are
three five two one seven I currently do
not have a datasheet for this thing as
it seems to be so new that you can't
look it up I don't think it's a rebrand
or anything it is from the IR through is
thirty five to
100-series but yeah I can't get a
datasheet for it right now
so there is a 35 201 no 211 there's a
201 there's also there's a bunch of
other 35 200 series tips I'm assuming
this is going to be just another one of
those 30 well this has to be a six phase
voltage controller just because we have
one two three four five six
these are IR there oops that's a be IR
3598 but nonetheless this is just you
know it's going to be a six plus
something voltage controller because it
also controls the HBM vrm down here
which we have one driver I see right
there
but this is a 35 200 series chip so it's
going to it should do the usual 200
kilohertz to 2 megahertz switching
frequency range not that the upper - you
know the upper limits of that switching
frequency range really aren't useful
even here with the doubling scheme you
could actually go all the way up to 2
megahertz without having this erm catch
on fire for you but the problem is as
you really push the switching frequency
on vrm their efficiency just goes down
the drain
most MOSFETs are basically not designed
to function above 1 megahertz anyway
the ones on used on this card they will
function above 1 megahertz switching
frequency the IR 3598 can actually push
more than 1 megahertz switching
frequency output so you can push 2
megahertz into them but the problem is
your efficiency is going to be really
really bad so really that upper limit
does not matter though pushing this up
to say 1 megahertz switching frequency
might see some benefit but with this
being a 12 phase and with the decoupling
job that AMD does on these high-end HBM
cards I mean this is ceramic capacitor
city this is more like just ridiculous
amount of by decoupling capacitors right
there and then we have high-end just
these are SMD polymers these things are
literally the best option
for vrm capacitors and these are 470
micro farad so the chances of this vrm
needing more phases just to get stable
voltage regulation very very low I I'm
gonna when I get my card I'm going to
still try attach even more capacitors to
it but I really doubt I will see any
benefits and E is generally really
really good about getting ridiculously
stable voltage regulation on their
reference cards and this just looking at
the design we have here the you know the
IARC voltage controller which
incidentally this thing is digital so it
will support software voltage control
and then the IR 3598 doublers these are
not any and they don't have any advanced
features but they do interleave your two
phases so this does run cleaner than a
native six phase and the six days on the
fury X was excellent and you know it was
smaller so this is even a step up from
the fury X erm it's pretty much double
what the fury ax came with so voltage
regulation wise nothing to worry about
really like it doesn't get better this
is very much like this this vrm in terms
of control scheme excluding the fact
that this uses a different voltage
controller is exactly the same as what
you would find on a 290x lightning for
the vcore so I can't find any complaints
to to have about the control scheme
except you know maybe they could have
gone for the 16 phase but that would
kind of get really excessive that phase
count is really rare for a reason it's
generally pretty impractical so back on
the front of the PCB let's talk actual
power capabilities so the control of the
VRM is good there's nothing to complain
about there now the actual power
capabilities each phase has a single low
side mosa and a single high side MOSFET
the low side set is IMD's favorite IRS
68 94 this is a international rectifier
direct FET it is really easy to
recognize these because they have the
metal casing
this helps with thermal dissipation as
well as all well basically it's mostly a
thermal dissipation thing these things
are not cheap actually
they come in well over air off the top
of my head they're around 1.2 euros per
thousand according to international
rectifier zone website now the IR now
the high side MOSFET is the usual IRF
just because if you have a 68 94 this
one always cut goes with it it's a 68 11
and that is also a direct fat much
smaller though and worse thermal
handling capabilities but nonetheless
this combination of MOSFETs are like
this is the same you would find on a
290x lightning and with each with two
well with this set of MOSFETs in each
phase this VR I'm assuming in operating
conditions of 1.2 volts output 12 volts
input obviously it's in a it's powered
by an ATX PSU 300 kilohertz switching
frequency and 5 volts gate drive which
the 5 volts gate drive is very very
unlikely on this card it might even be
using 12 volts gate drive I am Not sure
these MOSFETs can certainly run on 12
volts however the thing is 5 volts gate
drive is the minimum operating voltage
for these MOSFETs well really is 4.5 but
4.5 volts to 5 volts it's the same thing
so I'm using the 5 volts gate drive
voltage because I without the card in
hand I can't check what the actual gate
drive voltage is and this will give you
the worst current handling capability
figures for this erm 300 kilohertz
switching frequency on the actual phases
themselves I'm assuming based off of the
fact that a.m. these past cards we're
running 300 kilohertz switching
frequencies so that would be 600
kilohertz on the controller there's a
pretty good chance that the actual phase
switching frequency is even lower than
what I'm using here so I feel pretty
safe in saying that any current figures
I writ list as well as he outputs are
worst case scenario certainly they're
not going to be driving the MOSFETs as
it's 5 volts that's no AMD card ever has
driven with 5 volts they usually drive
with 7 or 10 so yeah let's get into the
current figure so 200 amps which I don't
think the card will actually run on 200
amps just because we're looking at a 300
watt TDP and HBM does
not use a lot of power nor do any of the
other systems on the card 200 amps we're
going to be looking at around 23 watts
of heat output and on the MOSFETs not
inductors and capacitors included just
the MOSFETs will put out about 23 while
so heat output so that's the thing then
300 amps you're looking at 43 watts of
heat output now this I would say is
slightly above what the card will
normally use unless the card spends most
of its sitting most of its time sitting
at around one volt
I haven't yet gotten my card I can't do
checks on how the card runs under
typical loading
I generally when I do these analyses I
like to run with numbers from cards with
no power limit because then they don't
change their voltage on the fly making
it really easy to predict how they'll
behave when you really really crank up
the voltage instead of trying to figure
out what the actual peak current rod
that is like because basically if the
card is power throttling right it'll
drop the voltage it'll drop the clock
but your current will still be up which
is why it's still bouncing off the power
limit and then if the current drops down
it'll pull up the voltage and it'll pull
up the clock because you're pulling less
current but effectively your power draw
is still the same but if I kept the
voltage high and I didn't drop the
clocks because the power limit was
listed then your current would generally
just shoot through the roof so I'm not
currently sure how much power you would
need for overclocking because
overclocking you're obviously going to
do everything in your power to reduce
any kind of power based throttling or
temperature based startling and so as of
right now I don't have data on how much
power this erm will actually have some
handle when overclocked certainly for
stock power consumption this thing is
ridiculous overkill let's keep going up
the current figures so 400 amps the CRM
will put out 66 watts of heat that is
starting to get into the problematic
area the CRM is pretty spread out as you
can clearly see a good amount of surface
area on it so it's it's going to be you
know it's not going to be the hardest
thing ever to cool but sixty-six watts
of heat is a good amount like that's a
lot of heat so I know if you're
hammering this card the arm temperature
is our going to be work like you should
keep an eye on them however the mall
sets themselves can actually do 400 amps
of current even at temperatures as high
as 3 138 degrees centigrade so
everything else on the vrm will complain
at that point your your capacitors
definitely capacitors generally don't
come in ratings above 105 some of them
comment 1 125 degrees rating but those
are really really rare 125 degrees it's
still less than 138 so the MOSFETs won't
die if you run them really really haul
everything else on the vrm will however
suffer reduced significantly introduced
lifespans so yeah in our short-term
operation at very high like very high
current load loads possible not
recommended depends really on your VR
I'm cooling the arm can go higher 500
amps you're going to be looking at about
92 watts of heat output and it can still
go further as the I'm assuming that like
in this is assuming you can keep the vrm
at 125 degrees as MOSFETs do basically
as long as you're not hitting the
thermal Junction max of the MOSFETs you
can keep watching more current once they
exceed thermal Junction max they'll
thermal runaway and blow themselves to
pieces but if you can keep the vrm at
125 degrees even with the 92 watt heat
output then 500 amps you can totally
push that through it as well in fact you
can go all the way up to 700 amps
however at that point it'll put out the
same amount of power as ACE was a GPU so
this is basically it'll handle it in
short-term bursts the heat output at
those kinds of current levels is so high
you're not going to be able to cool it
however the good news is basically that
this vrm right here is certainly very
very capable in fact the mosfet
selection the driving setup and
everything but the voltage controller
here and the inductors and the capacitor
selection is the same as what you would
find on a 290x lightning so power wise
this VRM is on par with high-end custom
GPUs of a few years ago so yeah it is by
far the most powerful vrm we've ever
seen like ever on a reference card
this makes the GTX 480 SVR M look like a
bad joke and the GTX 480 would be the
only card I can think of that should be
in the same kind of current levels
because the GTX 480 came at extremely
low stock halted due to its ridiculous
power draw
but yeah this erm is just like it's a
thing of beauty but the side effect is
that leaves the question of does this
card really need 12 phases or is AMD
just being very generous you know if we
judge based on the length of our X 480
where the vrm was ridiculous overkill on
the reference card like it wasn't
exactly power efficient the MOSFETs
really weren't the best for power
efficiency but they were very very
capable MOSFETs that card had a really
liked that card out of VR I'm capable of
delivering two to three times its stock
power draw I will stall current
consumption and what we're looking at
here is you know it's really really is a
really nice vrm the question is does the
card pull so much power at stock that
this is actually necessary or is md just
doing what they did on the 480 where the
stock we are I'm was like you could take
a 480 in max like a reference 480 and
max it out on liquid nitrogen and the
vrm would not be the problem you've run
into so that is the that is the question
I'm still left wondering is just like I
mean on one hand AMD does have a history
of putting really nice crm designs on
their cards even the fury acts it's like
one point four volts the RM handles it
no problem even the cooler on the fury
ax will actually deal with one point 4
volts and more I've just not been brave
enough to go higher yet but yeah it's
just this is like this is literally
twice the fury axis erm so does it run
twice as much power at stalk as a fury
ax
I mean twice as much current at stalk or
you know I mean it is $1,000 cards so
maybe AMD just went the extra step and
actually gave us a vrm that's worth a
damn but kind of concerning kind of
concerning and leaves a lot of questions
to still answer at least for me now then
let's move on to the minor vrm then when
I say minor I mean less than one twelfth
of what the main vrm is this right here
is the HBM vrm it is a significant
downgrade compared to the recurve erm
it's a single phase we just have one
choke here and that power is in both of
the memory stacks and it uses a on
semiconductor dual and fat this thing is
nothing amazing it's a for cat6 and
that's not the full model number but if
you put that into google it'll find it
or into on semiconductors website it'll
find it so that's a dual line fat so
basically the high side MOSFET and the
low side MOSFET are integrated into the
chip this thing is not that great the
end result is that the CRM can do 10
amps at about 2 watts of heat output on
the MOSFET 20 amps at about 4 watts of
heat output which incidentally assuming
one well again I'm assuming these
operating specs for that MOSFET down
here and the reason I'm assuming that
1.2 volts not a higher voltage is
because HBM at least by SK Hynix spec is
meant to run on 1.2 volts now in the
past on the fury axe AMD was running 1.3
volts through the HBM but without a card
in hand to check I have no idea what
they're actually running it on I'm going
to assume that this time around the HP
m2 is actually working properly I hope I
really really hope that at this point
they can run the freaking memory at
voltage spec voltage instead of over
voltage just to hit the stock frequency
that it's supposed to do and I'm
assuming they're going to run 1.2 volts
300 kilohertz 5 volts gate drive again
so assuming those settings this 20 amp
figure 4 was heat output is actually 85%
efficiency which is just cool because it
confirms for me that my calculate V RM
calculation matches exactly the
calculation that they have on the
datasheet well more or less exactly it's
about 85% for both my calculator and
there and the datasheet so 20 amps 4
watts and then 30 amps you're looking at
7 watts
now I'm not going to go into any higher
current figures because really the HBM
on stock voltage should only be pulling
between 10 and 2
I think around 16 maybe 17 amps on stock
settings so it really doesn't need a lot
of power and that's why we're looking at
such a really small vrm so you know like
such a small vrm for it now then moving
on to the remaining minor rails we have
the well these three guys over here and
these are three different voltages I
don't know which one is which I'm not
sure how much any of these voltages pull
the datasheet for this these MOSFETs is
horrific ly useless in that it only
gives me ambient temperature is ax am be
like ambient air temperature ambient air
thermal resistance which is useless for
a GPU with a heatsink on the V R M that
is the main problem it's like where like
that 125 C figure right here that's
MOSFET like if you put a thermocouple on
top of the MOSFET that's the temp if
that's the temperature of the MOSFET
then this is how much current you can
push through it before it starts to go
you know thermal runaway on you
obviously if the temperature goes up by
one degree then you've just exceeded
your current limit and bam it goes
thermal runaway on you anyway but if you
put a thermocouple on there this is the
temperature that you'll measure and
these are the current levels it'll do
assuming you can keep it at that
temperature the problem is I don't have
the thermal resistance figure for these
for case temperature so basically you
put a thermocouple on these and I can't
tell you anything about what they should
handle ambient air temperature figures
like I don't know what kind of actual
operating temperature the MOSFETs will
hit but it looks like from the datasheet
any of these should be able to handle
about 10 amps these are all dual n sets
again and the voltages they're producing
are going to be VDD C I so that's the
memory controller on the AMD GPUs which
if you notice compared to gddr5 AMD GPUs
the VDD see i've vr m being one of these
three is actually a huge difference
because EDD CI on say something like a
rx 480 is actually very similar to this
so it's about twice to three times as
powerful as what you're getting right
here for
DCI because the big difference with HBM
you know you don't save that much power
on the HBM own voltage it's not that
different from gddr5 where there is a
huge difference is the memory controller
the memory controller for HBM is way
wave mate way more power efficient and
the end result is that we have a really
really pathetic little VD DCI vrm as
well as well it's not pathetic it's just
you know reasonably sized now so you
have a much smaller VDD see I've erm
compared to what you would see on a lot
of other cards now under well the other
voltage these we'll be doing is VPP so
this is a supporting voltage for the HBM
gddr5 x also has a VPP rail basically
this is a voltage that used to be
internal to gddr5 ddr3 and all of that
well ddr4 gddr5 acts I imagine whatever
comes after gddr5 x h PM h vm - all of
these have an external VPP and this was
done because it improves memory power
efficiency it used to be that the
voltage would be created on inside the
actual memory chips themselves here it's
made external because this is the more
power efficient way to generate it and
then finally the third one of these will
be the display drive ole tidge which I
don't have a nice shortcut for so I'm
just going to call it disp and that's
basically that powers the some of the
GPUs internal PLL's as well as the
display outputs this voltage is very
very useful when push when pushing AMD
cards on liquid nitrogen because AMD
cards on the quad nitrogen have a
tendency to lose their display outputs
as in your monitor will just go black
the cards still running the display
outputs just drop out and this happens
specifically under load when pushing
very high core voltages at very low
temperatures the display just stops
working for whatever reason and you can
fix it by bumping up the display output
voltage as that circuitry either gets
too cold or power starved or something
happens to it and it starts complaining
so yeah but none of these voltages are
well I think what man may or may not
have VDD CI voltage control currently
available VPP and v disp this one
basically does nothing for overclocking
this one is only relevant on liquid
night
neither of those going to be available
in software so you don't have to worry
about those really and yeah so that
covers all the VRMs um you know vcore
vrm could not like lovely i love it
it could not be well i it could be even
bigger but at that point i'd really
start questioning like is AMD just like
gonna start making extreme overclocking
cards out of the box making all the non
reference designs completely pointless
or even worse because that's actually
happened is like AMD's reference 7 970
PTV was just so nice and expensive i
guess that there was 7 1970s we've
downgraded p cds in fact there's RX for
80s with downgraded p cds so you know
it's like it's somebody like on nvidia
side it's like oh yeah we don't want the
reference card it's awful on AMD side
it's like sometimes the reference card
is actually the best and you know that
that's kind of starting to get ridicule
so weak or vrm I really like I have no
complaints about what I'm seeing so far
I'm just hoping that it's not indicative
of some ridiculous stock current
consumption the HBM vrm it is a single
phase and I will complain about that
because the like I'd like to see a
two-phase I it's just the HBM on the
fury X I know that ran stock HBM over
volted and it was just like you know
generally a mess but that that card
benefits from extra capacitors on the
HBM vrm which basically tells you it
should have had an extra phase because
the voltage isn't stable enough on a
single phase but here we do have a we do
have a single phase and it really like
it really depends I'm going to go and
test if you know I'm going to obviously
test if this single phase is enough I'm
hoping it is but judging from the fury X
it might not be so it's just going to
throw that out there and then the minor
ones is like you can't control VPP I
don't care about even as an extreme
overclockers I just don't care MIDI DC I
really shouldn't pull enough power to be
concerning and V this but never does
that one has been
10-amp basically can amp fully like
fully integrated but converter chip for
ages and ages and ages and it's never
actually pulled the 10 amps and it's
basically completely irrelevant for
everything except liquid nitrogen
overclocking so the are my is the card
is fine
now let's look at some of the cool
features that this also comes with this
right here is a dual BIOS which which is
standard for all high-end AMD reference
cards you'd find this on a7 970 I think
even by 5 7 nope 580 70 doesn't have it
but 6 970 yeah 69 70 has had it to 7-9
70s had it - 90 - 90 s - 90s - 90 X's
had it
fury axes have it Vega now has it so you
know bring that on I love BIOS modding
and the BIOS which is really nice I just
hope there's not going to be any more
BIOS bio signature checks in the driver
because that is those always just you
know rain on your parade but it is nice
that you at least get dual BIOS the boss
there's one BIOS chip right here there's
another one on the back of the card
right on the basically mirrored with the
BIOS chip on the front except tweaked by
a little bit on the angle and then the
last cool feature that has is the GPU
tachometer right here which is basically
a strip of LEDs it's I think it's really
cool a lot of people think it's useless
fluff like all the other RGB we see
these days but this is actually useful
because this delivers you know it's not
system critical information like voltage
or temperature but it's really useful
for debug like figuring out what's wrong
with like a crossfire setup because it
will show you if you LPS is enabled it
will show you if the cards aren't being
loaded up properly and that's about it
really it'll pretty much tell you it's
like are the cards running the way they
should be because this does indicate GPU
load so very nice for you know if if
you're running if you're doing what I do
this comes in handy every so often which
is a lot better than most of the RGB
stuff where it's like oh like yeah it
looks nice and also the cool thing is
which a lot of people on the fury cards
weren't aware of there's a
little switch right here this is a
two-channel dip switch you can change
the color on the fury axes this was red
in blue
I assume it's red and blue again I would
hope that it would have been blue in
yellow because the card is blue and
yellow and that would be
color-coordinated but I'm going to just
guess that it's blue and red anyway but
you can turn change the color of the
LEDs and you can completely turn them
off using that switch so that's it for
this video you know I hope you found it
informative you can leave a comment down
below if you have any thoughts or
questions to share you can like the
video if you like to dislike it if you
disliked it please consider donating to
the gamers Nexus patreon if you would
like to see us do you know if you would
like to support what we do here if you
would like to see more content like this
and more overclocking videos then I have
a channel called actually hardcore
overclocking you can go watch all kinds
of hardcore overclocking related stuff
like liquid nitrogen overclocking that
kind of thing over there that's it for
this video thank you for watching and
see you next time
you
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.