- A thousand watts, that is the recommended power budget
for this GeForce RTX 4090 from MSI.
In this economy?
No wonder gamers are outraged.
But what if I told you there's another way?
What if I told you I'm gonna ditch
my 1,000W power supply
and run this top-spec gaming rig
complete with RTX 4090 on just a 550W power supply?
There will be trials.
Oh crap.
There will be tribulations.
Ah crap!
Come on!
But I will be darned, darned I say,
if I'm gonna have you guys paying full price to run your rig
after you, (coughs) wisely blew your savings
on a video game machine.
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- So first things first,
do you even need a 1,000W power supply,
or is this whole thing overblown?
To find out we've dusted off our Nvidia PCAT,
an inline power measurement device designed for GPUs,
and we've yanked together a PCI-e Y power splitter
to accommodate the four bloody 8-pin PCI thrust
connections that you need for the 12-pin adapter
for this GPU.
You see the PCAP (clears throat) was designed
in the before-fore times when nobody ever thought
you'd need more than three 8-pin power connectors
for a single graphics card.
I wouldn't describe this as our most stable GPU ever
but I don't think it's going anywhere.
There are a couple of ways that we're gonna monitor
our power consumption.
First of all, we've got the PCAT
that I just mentioned before, tells us the GPU's power draw,
then we're gonna have a regular wall power meter
which is gonna tell us the total power draw of the system,
including any losses due to the inefficiency
of our power supply.
We'll kick things off with a real game,
in this case, Cyberpunk 2077 running at 4K,
mostly high presets, with ray tracing set to medium,
and our GPU is sucking back a whopping 430 to 470W
with our total system power consumption at about 600W,
all while running at a cool 50 fps.
Boy, is this ever a demanding game,
almost as demanding
as MSI's Kombustor stress testing application.
Wow, it's a little lower even.
I guess any additional load
that Kombustor puts on the traditional
rasterized rendering course is more than made up for
by the activation of the ray tracing course in Cyberpunk.
We're gonna need ray-traced fricking stress tests.
What the heck?
Whatever the reason, it's pretty clear
that we don't need a 1,000W power supply
to run this card, which makes sense, I guess,
given that Nvidia themselves only recommends
an 850W unit for their founder's edition version
of the 4090, which raises the question,
why is MSI asking you to spend extra money
on a 1,000W power supply?
If I had to guess, I'd say it's for two reasons,
first, to accommodate for any extra power draw
from overclocking, and second,
to account for our connected peripherals
like bus-powered USB devices, hard drives, LED strips.
The last thing they want is for you
to plug a bunch of other stuff in
and then come crying to them when your system shuts down.
Which raises the question,
how much more power could we draw in their OC load?
As advertised, system power consumption is up
in the neighborhood of around 10%,
but unfortunately it didn't have the impact on FPS
that I might have expected,
we've gone from about 50 FPS to anywhere from 50 to 54,
which kinda raises the question,
has Nvidia already got the 4090 absolutely redlined?
And if that is the case,
could we maintain nearly the same performance
but drop our voltage for a big bump in efficiency?
The first step in our journey is to drop back down
to default mode, shut down the system,
and try again with MSI's minimum recommended power supply,
an 850W.
Tech tip for you guys, you should never do what I'm doing,
where you swap out a power supply
and use the same modular cables,
and the reason that you shouldn't do that
is because they might not actually use the same pin outs
and you can accidentally fry the devices on the other end.
In our case, we have painstakingly validated
that these use exactly the same pinout
but we still don't recommend it.
Do as I say, not as I do.
Bzzp, ah, no!
No, I'm just kidding, it's fine.
Even within the same manufacturer,
they're not always the same pinout.
As expected, our performance is identical
with our 850W power supply,
as is our system power consumption
at around 630W from the wall,
meaning that it is probably safe
to run pretty much any 4090
on a good quality 850W power supply,
and that 1,000W recommendation seems to be more
about butt covering than any actual concern
for over-current protection kicking in
and shutting off your computer.
But if 850W is fine then perhaps 750W is also fine.
I mean, it still only says 600W from the wall, right?
And that's accounting for the power supplies inefficiencies,
it's only like 550.
I think we're gonna get there.
If these donuts in the middle of the intersection
are anything to go by, 750W is fine just fine
with a 100+ watt buffer, but that's not to say
that every 750W power supply is gonna handle
a Ryzen 7000 and a 4090,
there are a couple of major factors to consider.
First is transient spikes,
we first noticed this with the RTX 3000 series
but power-hungry GPUs like this one can momentarily draw
far more power than what they are rated for.
It's not for long enough to cause thermal problems
like, usually, only for a few microseconds,
but it can be enough to trigger the over-current protection
of your power supply, especially if you're running
an older unit that wasn't designed
for modern beast GPUs.
Another factor we're not considering here
is capacitor aging.
This power supply probably only has a dozen-or-so hours
on it, at most, give it another 100,000 hours,
and depending on factors like how hot or cool
it was running, it could be operating at maybe 95%
of its brand-new capacity, or 90%, or even much lower.
By choosing a properly-specked unit with plenty of headroom,
you give yourself a better chance
of years of trouble-free operation
and help avoid catastrophic failure.
'Cause the thing about power supplies is,
when they pop, they can sometimes take
everything else with them,
which won't stop us from seeing how low we can go.
Where's my 650W power supply?
I know where it is, I'll get it.
Now we are running into a situation
where we've actually run out of 8-pin power connectors
coming out of our power supply,
so we're going to have to employ, (groans) a splitter!
All the Y splitters.
You know, Y splitters, like, why?
Sorry, Sea Sonic, you guys were a great sponsor,
I apologize in advance for blowing up
your power supply on camera,
hopefully we can work together again in the future.
It's probably fine.
What will probably happen is we will trigger
the over-current protection of our power supply
and the system will just (clicks tongue) shut off.
We do need to drive around a bit
before we say for certain this is working.
It puts a little bit more load on the GPU,
I saw it at 620 there,
basically we could put a couple LED strips
on this system, and it could put us over the limit.
For those of you wondering,
by the way, we stopped using Kombustor
because the load wasn't even as high as Cyberpunk,
I thought it would be higher.
Oh, one thing we could do is we could put a little bit
of CPU load on the system.
Cyberpunk is still running in the background
and what will probably happen is the game,
I will die in the background,
and it won't actually be rendering.
567, 740.
Oh, get this, Brandon, how is it doing that?
That doesn't seem right.
Sea Sonic, hello?
Our FPS is N/A.
We've left this plane of existence behind.
No, GeForce Experience, it's probably just bugs
that happens sometimes, but I was not expecting this.
I guess it could be that their 650W unit
is simply over-specced
and they set their over-current protection
for something far in excess of 650W.
The fan isn't even spinning.
Sea Sonic, what you doing?
I mean, that is the way to build
a really high-quality 650W power supply
is if it's just a 750W power supply and,
you know, with the seven scratched out,
just put a six there.
Let's go lower.
To be clear, I'm not expecting anything to happen
at the desktop, we're sitting at like 130W right now,
but I am expecting something to happen
because aside from going down from 650 to 550W,
we're also stepping down
from Sea Sonic's Prime Titanium premium power supply lineup
to their Focus lineup, which is, I mean,
it's still 80+ Gold, it's still Sea Sonic,
10-year warranty, blah blah blah,
but it's very unlikely that that's, you know,
an 800W power supply in 550W clothing.
Holy (beep).
Ah, this is not what I expected.
We are drawing 630W from the wall,
the GPU is at 450W.
You know we shot the intro
for this video with the trials and the tribulations,
I was expecting there to be crashes for us to cut in there.
I'm gonna have to, oh, oh crap, well, there's one.
Oh, but it's okay, we have a way around it.
First up in our bag of tricks,
instead of turning our power target up,
we are going to turn it down,
maybe 90% is enough to get by with 550W.
About 2,800 MHz is what we get on this one in default,
so as long as we're close to that, we are in good shape.
We'll also be able to tell from the FPS
the game is running out though.
Ah, crap.
Well, we're gonna need more than 10% power limit.
How about 80?
600W from the wall already?
Okay, come on, come on, come on, come on, come on.
Ah, crap, come on!
We're not defeated yet though.
We found we can go as low as about 70% power limit
without losing a ton of performance.
Oh, I really hope we make it.
70%, Apply.
Overall system power consumption is under 550W
at the wall.
Crap, crap!
We couldn't even get the close up.
But we aren't defeated yet.
We could drop the GPU down to 60, 50% power limit,
the issue is that when we do that,
we risk seeing some pretty funky behavior,
if our FPS still looks okay.
We might need to start attacking this
from a CPU perspective.
Oh crap.
Oh, this is not good.
(television beeps)
Actually, before we adjust our CPU, one thing we can try is,
remember how I'm running a Y-splitter
from one of my power supply outputs to two of the inputs
on our Nvidia power measurement board?
Well, there's a way that we could not do that.
We have four total outputs on this power supply,
and what we could do is we could just run
a single 8-pin to the CPU
and then three dedicated 8-pins over to this board.
I'm gonna step it back to 80% power limit.
I believe we were overloading a 12V rail,
not actually overloading the power supply.
Oh God, it's at 580 already.
Okay.
Darn it!
Brandon, you've captured plenty of the crashes so far,
you don't need to have all of my failures on film.
Oh, crap.
Ah!
Crap, come on!
I'm just gonna power straight into it.
70% power limit, let's go!
Yeah, it's still jumping up as high as, like, 360W,
that doesn't seem like 70% of the power limit.
Come on!
We're not done yet.
My hope is that we can save a bit
of our overall system power budget by reducing the voltage
to our CPU, relieving everything else on normal,
we've even got PBO, precision boost overdrive,
still enabled, which allows the CPU to turbo up higher
and for longer, but maybe by reducing the voltage just,
just 0.15 volts, will get away with something here.
We might have gone a little aggressive
on that CPU undervolt
but we also really wanna see this work so.
Go in game, in game.
(gasps)
We managed to drop our overall system power consumption
by, like, 20%,
and all it cost us was, we're running at 49 FPS right now.
Oh, 48, less than 10% of our actual real world performance,
we are running a 7900X and a 4090
on a 550W power supply.
As promised, even though I didn't know for sure
it would happen.
Of course, as cool as that was,
nobody's gonna buy a GPU like this only to leave performance
on the table.
Thankfully, you can have the best of both worlds.
We observed that our GPU clock was around 2.8 GHz
under sustained load,
so what we can do is go into the curve editor
in MSI Afterburner, hold Alt,
and take our very farthest dot here,
and drag our frequency target down to about 2.8,
then we're going to individually drag up
our 950 millivolt dot to, do, do, do,
2.8 gigahertz, and apply.
We've changed our target from 3 gigahertz to 2.8,
which is fine
because we were only hitting 2.8 gigahertz anyway,
theoretically, assuming we stay stable,
we should have our lower power consumption
and our stock performance, almost,
we'll get to that in a moment.
The Keenite among you will have noticed
we're back to our 650 rather than our 550W power supply.
We saw some very strange behavior with the 550,
so, dor this demo I just wanna show you
how the power consumption is low,
I don't need to be using a 550W power supply.
The game crashed.
Let's try 970 millivolts.
And there we have it,
even though we've backed off our CPU undervolt a little bit,
we're down to -0.1 volt and we're at 975 millivolts
on our GPU,
we are still like 100W lower
than we were when we started.
As for our performance, ah, a touch lower,
but we can fix that very easily,
all we gotta do is Alt + Tab out,
then we're just gonna play with our memory clock,
let's try +500, it's possible we could go higher than that
but meh, 500 is pretty safe.
Now we're back in game and (sighs)
I'm seeing as high as 60 fps,
but going back to the same area,
now it's more like, yeah, dropped under 50.
Ah, let's give the memory a little more juice.
Let's say 900, boop.
Still at 530, 540W, 52, 54, 60.
I'd say we are pretty darn near we started now.
Not bad for a 650W power supply.
All of this raises the question,
what if instead of going full balls out,
Nvidia did what we did?
We could have had smaller coolers,
more sensible power supply requirements,
nearly the same performance, like, in real terms,
that could be hundreds of dollars in savings over the years
that you might be expected to run a GPU like this,
but then it's also possible
that nothing would've been different,
maybe in order to get economical yields on Ada Lovelace,
RTX 4000's architecture code name,
they needed to accept these power-hungry parts
and maybe we just got a good one.
The good news though is that even if that's the case,
at $1,600, this is a problem that won't affect
a lot of people, and those that can afford this GPU
can probably afford the running cost.
Either way, it was an interesting adventure,
just like this interesting adventure into Segway Land.
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- So thanks for watching, guys,
if you liked this video, hit Like and hit Subscribe,
and maybe check out another video
from us like the RTX 4090 review,
full review we just did.
If you like graphs, we got graphs.