External GPUs: How Do They Work?

Nowadays, External graphics processing unit or, in short, EGPUs are the talk of the town. Why? Because it is rumoured that using an External GPU provides your old laptop much more graphics processing power than its internal one. What do you think? Does it seem true fact to you or its just a hoax that is being spread. So, in order to clear all of your confusions regarding EGPUs, I will discuss everything about EGPUs from how do they work to how much they cost & how much performance they increase in a laptop and most importantly, is buying an EGPU worth the money? Or is it just a waste of money? To know all the unfolded truth about EGPUs, just keep reading.

How to Connect An External Graphic Card To Laptop?

Connecting an External graphics card to a laptop is pretty simple. A graphics card is connected with a GPU dock which possesses basically a motherboard and a PCI Express X16 slot and many other necessary components like different controllers and ICs. To connect that GPU dock with the laptop, mostly Thunderbolt is used though many manufacturers provide their proprietary connectors in order to connect their GPU dock to only their laptops such as Alienware. So, if your GPU dock has Thunderbolt or other proprietary connector and so as your laptop has then you can easily connect these two but if the port and connecter of GPU dock and your laptop are different from each other then you obviously cannot connect them.

After successfully connecting the GPU dock with your laptop, you have to just install the drivers and the job is done here. Unlike this type of GPU docks that I have just mentioned, there are some others that only come with a motherboard and a PCI Express slot. In that case, one has to connect the graphics card manually and separately. That’s why researching before purchasing a GPU dock is a must. You have to find a GPU dock with the same interface that your laptop has. Also, you can research for whether the GPU dock comes with the graphics card or you have to purchase it separately. Some GPU docks provide some I/O ports like USB & Thunderbolt ports so, you can research for them too if you need this type of docks. Researches before purchasing provide you extra benefits for sure.

Will You Get Better Graphics Performance?

Anyway, GPU dock is connected with your laptop and It’s ready to go. Now, each and every graphics related tasks & processing are occupied by External GPU and it provides the outputs regarding those processing. It’s somewhat true that you will get performance boost from using a better External GPU but if that same graphics card worked as an internal GPU, it would provide much better performance. As a result, an External GPU comes with 10 to 20% or even 30% decreased performance in compared to the same graphics card which works internally. Hence, if you think that connecting an External GPU dock with high-end graphics card to your laptop offers you to play modern AAA games with high resolution graphics then you are most probably wrong.


Reasons Behind an EGPU’s Decreased Performance!

The two principle reasons behind the comparatively decreased performance of External GPUs are: 1) Interface Bandwidth 2) CPU Bottlenecking.

Interface Bandwidth Is the Most Important Factor!

As I have earlier said that to make a connection between External GPU dock and laptop, Thunderbolt is generally used and the latest Thunderbolt 3.0 provides a maximum speed of 5 GB/s whereas in case of an internal graphics card, PCI express is commonly known and PCI-E 3.0 X16 slot provides a maximum speed of 16 GB/s which is more than three times faster than Thunderbolt. As we all know that the amount of data that transfer from CPU to GPU for further processing, is huge so the speed is very essential for transferring the data and processing it as quickly as possible. You can see, how slow Thunderbolt is compared to PCI Express. Therefore, there is no way an External GPU can work as fluent and fast as an internal GPU.

Know More: What is Thunderbolt? Versions & Features

CPU Bottlenecking Is Also Crucial…

This is kind of a common sense that you will most probably purchase an External GPU when you laptop’s Internal GPU is not strong enough to process your required graphics related tasks but the fact that you should remember is when a laptop’s GPU is not strong enough, it most possibly indicates that the CPU of this laptop is also not strong. So, if you think that using a powerful External GPU makes your laptop to complete all the graphics related processing with ease then sorry my dear, you’re in a wrong way. As the CPU is not so strong, it cannot transfer enough amount of data to the comparatively stronger GPU although GPU has the ability to process it. For instance, you are playing a game in 60 FPS in your laptop that uses your External graphics card which is comparatively more powerful than your laptop’s CPU.

Now, we all know that a GPU generates the frames one by one but the information that is required to gener ate those frames are sent by the CPU. So, if your laptop’s CPU is weaker than the External GPU, it will take time to send the information to the GPU though that GPU can easily generate the frames at a faster rate and then, GPU has to wait for when the CPU will send next information. At the end, this will decrease the FPS of your game. So, you can understand that the weaker CPU just hinders the performance of the much stronger GPU. That’s why CPU should be the same powerful as the GPU or it’s just a waste of money to buy a very powerful graphic card for your laptop’s weak CPU. And, if the CPU is powerful enough, in most cases, the GPU also comes with that same power and quality so in that case, there is no need to buy an external GPU.


External GPUs for Laptop – Worth the Money?!

Though, it’s sure that connecting an powerful External GPU may increase the graphics processing power of your laptop, it’s still not preferable because of the cost it requires. Along with a GPU dock, a decent graphics card cost around 400 USD and if you go for a high-end one, it will cost more than 1000 USD. So, observing an External GPU’s performance, I think that it’s too costly for a user to buy an External GPU and this is just a waste of money rather I would suggest that in that price, one can easily assemble a quality desktop that offers you multiple better components from processor to GPU, everything and it will definitely be much more beneficial for you than to buy an EGPU.

  • Check Current Pricing On Amazon (US)
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Therefore, I really appreciate the concept of using External GPUs but honestly speaking, this concept should be improved skilfully in the near future so that the consumers can get their required profit out of it. Till now, External GPUs are of almost worthless, inconvenient, and waste of money. Still, if you have decided to purchase an EGPU then obviously, first & foremost research properly for what exactly your criteria are. Lastly, I hope that you have properly understood; “External GPUs: How Do They Work?”. If this article has really helped you then don’t hesitate to express your valuable thoughts about this in the comment section. Thanks for visiting and appreciating my work.

Soumyajit Das

Soumyajit Das is our honorable founder & the CEO of our website, www.geekysoumya.com. who founded this website in 2018. Inspired by his wisdom as well as knowledge in technology, we become his disciples. Every gadget is his friend & he is well-known about how to care them. Now, he has one determined motive in his mind & heart i.e. to share logical & scientific knowledge about technologies so that every tech lover can learn something useful, something essential about their technological devices. Moreover, when you learn that scientific knowledge, your life will much easier & safer with your tech gadgets. Our CEO, Soumyajit Das is also in charge of all the technology-related topics on this website. He himself writes all the articles regarding these topics. On the other hand, other authors are there to handle the rest. With passion & zeal, he is giving labor to this website

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