I added this $3800 eGPU setup to a $100 laptop, but how does it perform in games?
We’ve got the ASUS ROG Matrix, the most powerful liquid cooled RTX 4090 graphics card
mounted onto an open bench table and powered by this 1300 watt power supply.
The graphics card plugs into an external GPU connector, which has a Type-C Thunderbolt
port for connecting to the laptop.
Our cheap laptop has an 8 year old dual core processor and 8 gigs of RAM, so not exactly
a gaming beast.
This model can be picked up second hand for around $100, it was just the cheapest laptop
with Thunderbolt support.
And this lets us connect to the overkill eGPU setup with just one cable, and then Windows
just sees it as a normal graphics card after installing Nvidia drivers.
This takes the laptop from not being able to run games at all on its integrated graphics,
to playing modern games at 4K max settings, but there’s a serious problem.
Just check out the stuttering in Cyberpunk 2077.
Even at 4K, which is a super GPU heavy workload, the RTX 4090 is hardly getting used because
the dual core CPU is at its limit.
But if we turn on features like DLSS super resolution and frame generation, well the
CPU is still the limit and it’s a bit choppy, but the gameplay is definitely smoother and
less jarring.
So the game is kind of playable like this, but look at how our eGPU setup in red compares
against other laptop and desktop GPUs.
The average FPS is pretty close to 4060 Ti and 4070 desktop cards at 4K, at least when
in a desktop PC and not in an eGPU setup.
There are just way more dips in performance with the eGPU setup, as shown by the much
lower 1% low number, so FPS is just less consistent with the eGPU.
A 4090 desktop card installed in a proper gaming PC with an i9-13900K CPU was 178% faster!
Not only that, but the eGPU setup is getting the same FPS at 4K, 1440p and even 1080p resolutions.
You could literally get an RTX 4050 laptop for just 20% of the cost of the eGPU setup
which would perform way better at 1080p.
But why?
The simple reason is bottlenecks.
Yeah, we’ve got this insane beast of a GPU, but it’s just limited by our 8 year old
dual core CPU.
So even if we stick in a way cheaper GPU it’s probably going to perform much the same.
But what if we use a newer laptop with a more powerful processor?
This is MSI’s Prestige 13, an even smaller 13 inch laptop, but with a current gen i5
CPU that’s 8 years newer than our $100 laptop.
I can’t find this exact model for sale, but the 12th gen version from last year is
on sale for $600, or the higher tier i7 13th gen version is $1000.
The performance from the newer 13th gen CPU absolutely destroys the older laptop, whether
we’re talking about single core which was scoring more than twice as much, or multi
core, which was more than 5 times better.
So does spending more on a better laptop help out the eGPU setup?
A little, but ultimately, no, not really.
Yeah, the average FPS is better compared to the cheaper 8 year old laptop, and at 4K it’s
at least better than a 4090 gaming laptop now, but only in average FPS which doesn’t
tell the whole story.
There are still more dips in performance with the eGPU, as per the lower 1% lows, which
outlines the stuttering.
And again, the FPS doesn’t change at lower resolutions, so at 1440p it’s less impressive,
and worse than a 4060 Ti card in a desktop PC, and then at 1080p it’s just straight
up embarrassing, with again that far cheaper 4050 laptop still winning.
But why?
This is where the next bottleneck comes into play, the connection between the laptop and
4090.
Seriously, just check this out.
This 3DMark PCIe test shows us how much bandwidth is available to the GPU.
Running a 4090 graphics card in a desktop PC results in more than 10 times the bandwidth!
The problem is just that Thunderbolt 3 and Thunderbolt 4 are both limited to 40 gigabits
of bandwidth.
Thunderbolt 5 is meant to be coming some time in 2024, and that doubles the bandwidth up
to 80 gigabit, though I think in some cases one direction is 120 gigabit, but I believe
that eGPUs will be limited to 80.
And this should definitely help address this bottleneck.
But it’s still not going to be anywhere near as good compared to running the graphics
card in a desktop PC with a full PCIe slot.
But I will be comparing Thunderbolts 3 and 4 against Thunderbolt 5 with an eGPU setup
as soon as I can, so make sure you’re subscribed for that.
There are faster alternatives to Thunderbolt, like connecting the eGPU to the laptop via
an M.2 slot, as these use PCIe lanes.
Unfortunately both of the laptops I’ve tested only have one M.2 slot, and it’s used up
by their SSDs.
Plus I don’t really see that as being a practical solution.
To me, the whole point of an eGPU setup is so that you can take your laptop with you
anywhere you need to go and just plug in one cable when you get home to dock and then get
access to a bunch more power.
I just think it kind of defeats the purpose if you have to mess around with taking off
the bottom panel of the laptop in order to plug the eGPU in.
At that point you might as well just get a small desktop.
At the moment, ASUS have the best eGPU solution in my opinion, with their XG Mobile eGPU.
But this is because their ROG Flow laptop series have this special proprietary port
with direct PCIe connection, which is obviously nowhere near as globally compatible compared
to a Thunderbolt Type-C connector.
Check out this video next to find out why the XG Mobile is so much better compared to
a Thunderbolt eGPU setup.