What happens when we connect Nvidia’s RTX 4090 to a small 14 inch gaming laptop?
I’ve tested it in 20 different games at 3 different resolutions and compared it against
running the 4090 in a desktop PC to find out the differences!
I’m connecting the 4090 to the laptop using Thunderbolt with Razer’s Core X Chroma external
GPU enclosure, so basically the 4090 connects to the laptop with a single Type-C cable.
The 4090 is so massive that it didn’t actually fit by default, I had to mod the enclosure
a bit.
Check out the differences between the 4090 and last gen 3090 Ti, we can see this bit
of metal on the 4090 is a bit thicker.
This small difference is all that stopped the 4090 from sliding into the enclosure,
but I was able to use a flat head screwdriver to bend this piece of metal in the enclosure
so that it could fit.
Not exactly perfect, but hey it worked.
Now the next limit of the eGPU enclosure is the 650 watt power supply with just two 8
pin power connectors.
Technically the 4090 can run with 3 8 pin connectors, but ideally 4 is preferable and
650 watts might be a little low.
Nvidia recommends an 850 watt power supply, though they note that this is when paired
with a 5900X CPU, and we’re not running a full desktop PC here, just the GPU in a
box, so less than 850 watts is probably fine.
I don’t have a small form factor power supply to swap with, so I’ve literally just connected
a random 850 watt power supply and put it next to the eGPU.
Of course this means we can’t close its case, but at least the 4090 can get enough
power now.
And yeah, I do realize having an abomination like this kind of defeats the purpose of a
smaller eGPU setup, I’m just doing what I’ve got to do to make this work.
I’ve used two laptops to do this testing.
The first is the ASUS ZenBook 14, a small 14 inch device with Intel’s Core i7-1260P
CPU.
This 12th gen processor has 4 P cores and 8 E cores, so to find out if this would be
a limit I’ve also tested with the Aorus 17X, a larger 17 inch gaming laptop with Intel’s
Core i9-12900HX, which has 8 P and 8 E cores.
So the same amounts of cores and threads to their desktop 12900K.
The desktop system on the other hand is basically a best case, with AMD’s Ryzen 9 7950X, a
16 core 32 thread part, not to mention much higher power limits as it’s not subject
to the smaller space of laptop cooling.
Here’s a quick comparison to show you the differences in raw CPU performance between
them.
The laptops are significantly behind in terms of multi core performance, but single core
differences weren’t actually that big.
As expected, the 12900hx demolishes the 1260p in the smaller machine.
So there’s clearly a CPU performance difference between those two laptops, and that’s why
I’ve tested both of them, to find out how much of a difference this makes in games with
an eGPU setup.
Generally laptops that have a higher tier CPU will also be paired with their own discrete
graphics.
My Aorus 17X for example has an RTX 3070 Ti, but the smaller ZenBook only has Intel’s
integrated graphics, as it’s not really a gaming laptop.
So the 3 main questions that I want to answer in this video are, number 1, can we use an
eGPU setup to boost gaming performance on a laptop that isn’t really designed for
gaming.
2, how much of a performance difference is there between a lower tier and higher tier
laptop CPU, and 3, how does our eGPU setup compare to just running the 4090 in a desktop
PC, as Jensen intended.
Just before we get into the 20 game comparison, check this out.
I’ve used the 3DMark PCIe test which tells us how much bandwidth we’ve got between
the RTX 4090 and the CPU.
It’s no surprise that the desktop PC has way higher bandwidth, but I wasn’t expecting
the laptops to be so low.
Thunderbolt 3 and 4 use 4 lanes of PCIe Gen 3, so we’re limited to around 4 gigabytes
a second, however an eGPU sees around half of this as some bandwidth is dedicated to
other things like USB and display.
Our desktop system on the other hand has 16 lanes of PCIe Gen 4, so yeah way more bandwidth.
And this will affect game performance.
Now Intel recently shared some information around their next generation of Thunderbolt
which will be based around USB 4 version 2, no idea why they couldn't just do USB 5, but
here we are.
More confusing naming aside, it looks like this will double bi-directional bandwidth
from 40 to 80 gigabit.
This will be a welcome improvement for improving eGPU performance, but clearly it’s still
not going to be able to compete with what a full on desktop PC can offer.
I also need to note that I’m testing with a monitor connected directly to the RTX 4090.
If we were to instead test with the laptop screen then we’d expect even lower performance,
both because we’re using bandwidth to send the display signal back from the 4090 over
the Type-C cable to the laptop, but also because the laptop’s GPU needs to process what it’s
receiving to show it on the laptop screen.
So just more overhead.
Long story short, although the RTX 4090 is certainly powerful, it’s going to be limited
by Thunderbolt bandwidth and our laptop processors.
So let’s see what the differences are in 20 different games!
Let’s start out with God of War.
I’ve got the 1080p results down the bottom, 1440p results in the middle, and 4K up the
top.
At 1080p and 1440p, the higher tier 12900HX in the Aorus gaming laptop was reaching higher
average FPS compared to the lower 1260P in the ZenBook, but the dips in performance as
measured by the 1% lows were actually worse with the superior CPU.
This flips around at 4K, but they’re both quite close, and although the desktop was
53% faster compared to the ZenBook, it’s still kind of impressive that we’re now
able to get above 100 FPS at 4K high settings considering this laptop only has integrated
graphics inside.
Halo Infinite on the other hand was performing like trash with the eGPU setups, the stuttering
was noticeable when playing, not something you should have to deal with when spending
$1600 USD on an RTX 4090.
You’re clearly going to want to go with a desktop PC instead of a laptop here.
Before you comment that’s because laptops suck, the RTX 3070 Ti in the Aorus 17X can
actually run much better than the 4090 eGPU at both 1080p and 1440p resolutions.
The 4090 should be way better, so this really illustrates current Thunderbolt limits.
Things are also pretty weird in Red Dead Redemption 2.
The FPS coming out of the laptops wasn’t changing at different resolutions, implying
a bottleneck, whether that be CPU or Thunderbolt, but what was strange was the lower tier i7-1260P
was reaching twice the FPS compared to the higher tier i9-12900HX in the gaming laptop,
and I have no idea why.
The last time I tested a Thunderbolt eGPU in this game I found it running around 30
FPS too, so perhaps this game just hates an eGPU setup.
Assassin’s Creed Valhalla was also running like absolute garbage on the higher tier 12900HX
laptop.
The smaller ZenBook 14 was actually fairly reasonable and definitely usable, but the
1% lows on the bigger laptop made it unusable.
I was so concerned that something was wrong that I spent hours troubleshooting, but nothing
I did improved it.
I even ended up reinstalling Windows and starting over from scratch, but I got the same results,
so again another example where I definitely can’t recommend an eGPU setup.
It’s not all bad though, Metro Exodus Enhanced saw similar performance from both laptops,
and although they’re much lower compared to the desktop, I’d say this is at least
usable performance now.
That said, when you’re spending 4090 money I don’t think you’re after just usable
performance, you want the best.
Honestly based on these results, you’d probably be better off spending less on a desktop PC
with lower tier graphics card and then a cheaper portable laptop instead of going the eGPU
route.
Call of Duty Warzone was tested in the practice area, as the goal here isn’t to show you
what sort of FPS to expect in real gameplay, because that’s too difficult to reliably
compare when people are shooting at you, but instead to fairly compare the different setups.
Strangely the lower tier i7-1260P was significantly ahead compared to the higher tier i9-12900HX
in the larger gaming laptop.
The desktop setup was giving double the frame rate compared to the laptop, but then at 4K
the CPU difference starts to matter less as the workload shifts over to the 4090.
Now the desktop had a 41% lead over the laptop, and the FPS from the laptop was basically
the same at all 3 resolutions, again implying either a CPU or Thunderbolt bottleneck, which
isn’t too surprising.
Fortnite was also still reaching usable frame rates on the laptops, but there’s that keyword
again, usable.
I expected better with a 4090, but the fact is we’re just limited by the bandwidth available
by Thunderbolt.
This will of course change with next gen Thunderbolt, but the fact is the 7950X still has a far
higher TDP compared to any laptop CPU, and this is going to contribute to better performance,
especially in eSports titles like this at lower resolutions such as 1080p.
Watch Dogs Legion is yet another game where the performance on the eGPU setup was just
trash.
Seriously, 26 FPS with the RTX 4090 at 1080p?
Even a relatively cheap mid-range gaming laptop will destroy that.
There’s clearly a problem with running this game over Thunderbolt.
Considering that this is something I didn't notice as much a year or two ago, I'm wondering
if it's caused by resizable bar.
Could that require more bandwidth between CPU and GPU over our already slower thunderbolt
connection?
Unfortunately most laptops don't give us the option to disable it and find out.
Things were a bit better in Warhammer III.
Again consider the fact we’re taking a 14 inch laptop without its own GPU to running
at 83 FPS 4K high settings, pretty cool, when it works anyway.
The Witcher 3 doesn’t seem to have any problems either, granted it’s still a bit of a mystery
to me as to why the lower tier 1260P was able to beat the 12900HX.
You’d think the bigger gaming laptop with more cores, more threads, more cache, and
higher power limits would do better.
And yes, I did try disabling the iGPU and dGPU in the laptop and had the laptop’s
screen off.
No matter what I did, in more cases than not the smaller laptop was doing better.
As this was the case in so many of the 10 last games, I kind of gave up on testing the
other 10 games on the Aorus.
Apex Legends was doing surprisingly decent compared to the desktop.
169 FPS at max settings 4K is pretty great considering we’re just connecting one cable
to the laptop and gaming.
The average FPS wasn’t too bad in Cyberpunk, but the 1% lows were pretty terrible, and
this shows the noticeable stuttering that was present, so yet another example how hit
or miss the eGPU setup can be.
Poor 1% lows were also seen in Rainbow Six Extraction and Forza Horizon 5.
The average FPS looks good, but the stuttering is what really kills the experience.
DOOM was running well enough, I mean 200 FPS with well above 100 for the 1% lows is playable
at max settings for sure, it’s just that the desktop hardware is absolutely destroying
it so the gap is huge.
The FPS from the laptop was all the same in F1 2021 too, which again implies a CPU or
Thunderbolt bottleneck, so spending more on the 4090 with this laptop probably isn't worth
it.
A lower tier graphics card would probably give you similar if not the same result.
I’m going to skip through the rest of the games as there’s nothing too new compared
to what we’ve already seen, so feel free to pause the video if you want a closer look
at any of these results.
So should you get an eGPU setup?
Honestly, based on this testing, I’d say probably not.
Especially with the RTX 4090.
When it does work, it certainly can be impressive.
But in more cases than not, random games just had different problems, resulting in a poor
experience.
The fact that in some cases a mid-range budget gaming laptop could outperform the 4090 in
games at 1080p is just embarrassing and shouldn’t happen.
But that’s just presumably the limits of current Thunderbolt implementations.
The laptops were often bottlenecked, whether that be due to the CPUs or Thunderbolt.
It was also strange that the lower tier CPU in the ZenBook was more often than not beating
the higher tier CPU in the Aorus, which objectively has a superior CPU in every way.
My money is on some kind of Thunderbolt problem.
Considering that even the 3070 Ti in the Aorus could beat the 4090 in some games.
So at the very least, this does show that you probably shouldn’t go for the 4090 in
an eGPU setup.
You could probably spend less money and get a lower tier card.
You’re just going to be bottlenecked the same anyway.
If you are going big and spending on the 4090, you kind of want to be able to use the whole
4090.
Now as mentioned, Intel has teased their next gen upcoming Thunderbolt version, which will
double the bandwidth and that will certainly help for eGPU gaming.
It’s clearly not going to close the gap between eGPU and desktop, but it should help,
and I look forward to comparing the old Thunderbolt against the new Thunderbolt with an eGPU as
soon as it’s available.
So make sure you’re subscribed for that future comparison.
For now, you can find out how much better the RTX 4090 is compared to the best from
last gen when we’re not limited to Thunderbolt or laptop CPU bottlenecks, so I’ll see you
in that one next!