Should I Buy an eGPU? 5 Aspects to Consider

Laptops with extremely high-speed ports—USB 4, Thunderbolt, and OCuLink—are becoming more common. One of the consequences is external graphics cards (eGPUs) becoming less of a niche product. Is it something you really need? Here are some things to consider.

Pricing: eGPUs Are Still Very Expensive

A good eGPU case will cost you no less than a few hundred bucks. That’s just for the enclosure, the actual graphics card requires yet another purchase. You can always use one you have lying around, of course.

There are reasons for this price tag. A GPU enclosure isn’t as simple as, say, an adapter to use HDMI cables with laptops that only have USB-C ports. Converting the graphic card’s PCIe interface to the smaller connectors used in laptops requires complex—and expensive—parts. The case also needs to provide proper structural support for the always-heavier GPUs, a decent cooling solution, and a power supply for the card’s needs.

Processing Power: Perhaps You Don’t Need More

If you use your computer only for web browsing, document editing, and light gaming (like older titles, or ones without complex 3D graphics), then you really don’t need an eGPU. You’ll likely don’t even need a dedicated graphics card in your laptop.

You might be tempted to get one “just in case.” However, present-day integrated graphics cards (iGPUs), the ones that are part of your computer’s main processor, are more than enough for all the aforementioned tasks. They’re even capable of running multiple displays without breaking a sweat—I write using a multi-monitor setup powered by an iGPU daily.

If your laptop has a dGPU (Dedicated GPU) it’s also highly-likely that an eGPU won’t net you a worthwhile performance uplift in most cases.

Operating System Compatibility: It May Not Work

In general, you should have no issue getting eGPUs to work on Windows, but those who prefer Linux for gaming may have a hard time dealing with eGPUs. If you favor macOS, your mileage may vary. Let’s get into detail for each case.

Linux support varies widely depending on the distro you’re running, which graphics card you have, and sometimes even the eGPU enclosure. Some manufacturers, like Framework and Kubuntu Focus (the former officially supports a couple of distros, while the latter is related to one), offer full support for external graphics cards. In other cases, however, finding a manufacturer plus distro combination that works for you may be tricky, as can be seen in the eGPU.io forum.

If you use macOS, you’ll fall under one of two possibilities: Macs with Intel processors can use external graphics cards without much hassle—there’s an Apple support page listing which models work, all of them by AMD. At the eGPU.io forum, users have a list of unofficial solutions that work with more cards. Apple Silicon Macs, though, don’t work with eGPUs at all.

Physical Space: eGPUs May Clutter Your Desk

Most eGPU enclosures (the Razer Core X being a notable exception) aren’t the size of a desktop computer. External graphics card cases, however, can’t by any means be called tiny. They’re meant to be external, but not necessarily portable, mind you.

If you have limited desk space, putting an eGPU case next to your laptop, All-in-One or mini PC, might add too much clutter. There are smaller enclosures, but those are limited to entry-level cards—or even laptop GPUs. Some models, like the Asus ROG XG Mobile, double as laptop docks, and can even save a bit of space.

If you’re going for a desktop-class eGPU, though, be ready to lose some desk real estate.

Bottlenecks: The Needed Upgrade May Be Somewhere Else

Before, we asked you to consider if your current setup doesn’t already fulfill your needs. If the answer is “no”, then you need to make sure your bottleneck is on the graphics card. We’re talking about investing hundreds of dollars in a solution. It would be terrible to part ways with all that money just to find out you’re still not getting the improvement you needed in the first place.

A bottleneck is the slowest component of your setup. It’s highly likely that either your CPU or GPU is the culprit, though other parts may be to blame sometimes. A GPU bottleneck manifests as the graphics card setting the pace in tasks related to the graphics card, like most 3D games or video rendering.

A GPU bottleneck isn’t a problem by itself, and in general you want your GPU to be the limiting factor for 3D applications, and not other components like the CPU. The only real question is whether your GPU offers enough performance at the fidelity level you need.

One of the most straightforward ways of finding your bottlenecks is using the Xbox Game Bar on Windows, which includes a resource monitor for processor, RAM, VRAM, and GPU. Start the application or task, then press Windows + G to check which component is limiting your performance. If the GPU load is consistently at 99% or more, that’s a sign of a GPU bottleneck. If your VRAM usage is 99%-100% all the time, then it may specifically be a lack of VRAM that’s affecting performance.

Performance: eGPUs Aren’t That Powerful

If you want an overwhelming performance boost, eGPUs are likely to disappoint you. Most models use Thunderbolt 3, a protocol which may be incredibly fast for file transfers, but isn’t up to the task for graphics card usage. GPUs deal with a massive amount of data, which is part of the reason why they use a specific type of connection, PCI Express (or PCIe for short).

PCIe is much faster than ports like USB 4 or Thunderbolt: depending on the version, it can reach 32GB/s, though modern (as of January 2024) high-end graphics cards only need about half of that. Thunderbolt 3 (and 4) goes up to ~8GB/s, while USB 4 reaches about 16GB/s.

As the math above shows, even the fastest cabled connections fails to match the speed of flagship GPUs—not to mention real-life data rates are lower than theoretical ones. Thunderbolt 3/4 and USB 4 are somewhat on par with the requirements of midrange models. However, the conversion between PCIe and Thunderbolt/USB leads to some bandwidth loss, leading to performance loss even with intermediate graphics cards.

If you’re using the eGPU to power the laptop’s internal screen, things get worse. The same cable that transmits the data requests from the computer to the graphics card needs to transmit it back from the eGPU to the laptop. That means double the conversion, and more data loss.

At the very least, you should expect an eGPU—an entry-level one—to perform 10 to 15% worse than if the same card was used internally. Flagship graphics cards suffer more significant drops, sometimes over 50%.

External GPUs are an interesting concept: they allow laptops to improve graphics performance—without sacrificing the computer’s portability—if you don’t need that much power while on the go. This flexibility may be the solution to your problems. It may not, too.

There are a lot of factors to ponder. They’re expensive pieces of tech, setting an eGPU up may present some challenges, and the performance gains aren’t exactly jaw-dropping. Because of all that, it’s always a good idea to double- and triple-check whether an external graphics card should be your next purchase.