External graphics card: More power for Thunderbolt

Graphics cards are the major weakness of laptops. An external graphics card promises to increase the GPU performance of the flat computer – but for a high price.

Anyone who wants to combine the best of desktop graphics cards and the mobility of a laptop will quickly come across external graphics cards, also known as eGPUs. These are graphics cards are connected to the computer via a separate housing and thus give their graphics power. Perfect for gamers who work with a laptop and want to play a game at home – without having a desktop PC.

Razer, Cooler Master, or Sonnet have already used “mini” cases with power supplies for graphics cards on the market. In the following, the article explains what buyers need to look out for with the eGPU and whether the investment is really worthwhile. By the way: Most cases come without a graphics card. You have to buy them.

Nothing works without Thunderbolt

A Thunderbolt 3 port is essential for docking an external graphics card to the laptop. It looks like a USB-C socket. However, it is usually identified by a small lightning bolt. The main difference to USB-C is that Thunderbolt provides higher data throughput. Typical devices with a Thunderbolt connection are MacBooks from Apple. Windows laptops such as the Razer Blade Stealth 13 or the Dell XPS 15 also offer the socket. Here, there is already the next hurdle to consider: With MacBooks, buyers of an eGPU are limited to a few AMD graphics cards.

This is due to MacOS and the lack of availability of appropriate drivers for Nvidia graphics cards. Because Apple mainly uses AMD graphics cards in its devices, the tech giant does not develop drivers for Nvidia hardware. And that’s why they don’t work as an external graphics card with Apple products. If you rely on Nvidia, you need a Windows laptop with Thunderbolt 3. Also, gamers have to consider the size of the case for the external graphics card. Powerful cards are particularly long and therefore do not fit into every housing. It is also important to consider the power supply: not every housing provides enough power for every graphics card.

External graphics card: the comparison

1. Razer Core X

Razer is very popular with gamers. If you already have a laptop and want to buy an external graphics card, the Razer Core X choose. Of course, the case also connects to other Thunderbolt laptops and MacBooks. However, it does not contain a graphics card. After all, its 650 watts power supply provides enough juice for most graphics cards. The case supplies the laptop with a maximum of 100 watts of power via the Thunderbolt connection. So, you don’t need to plug it into the socket with its power supply unit. Thanks to the plug-and-play function, laptops that also offer this feature do not have to be restarted when you connect the external graphics card. A restart is usually necessary for the computer to recognize the graphics card.

Size:33 x 16 x 6 centimeters
Weight:6.48 kilograms
Power:700 watts

2. Sonnet eGPU Breakaway Box 750ex

The Sonnet eGPU Breakaway Box 750ex supports graphics cards with a power consumption of up to 375 watts. Otherwise, it is similar to the Razer Core X. It also works with Windows and MacOS but unfortunately does not offer a plug-and-play function. According to the manufacturer, the case supports full-length, height, and double width graphics cards. With a weight of 3.2 kilograms, it is also 3.28 kilograms lighter than the Razer Core X. If you want to take the external graphics card with you on your travels, the Sonnet housing is a little better. 

Size: 18.5 x 20.2 x 34 centimeters
Weight:3.2 kilograms
Power:750 watts

3. Cooler Master MasterCase EG200

The Cooler Master brand is known to most gamers for its cooling solutions for processors, power supplies and cases. In the external graphics card segment, the manufacturer offers its Master Case EG200. At 5.4 kilograms it is not exactly lightweight. Otherwise, it is similar to the cases from Razer and Sonnet: The built-in power supply unit Cooler Master V Gold SFX offers enough power for power-hungry graphics cards with 850 watts. What sets the case apart is a USB hub and vertical laptop stand. The integrated hard disk and SSD dock on the front is particularly practical. You can use it to exchange various SSD storage media effortlessly. Ideal if you save projects for work on one hard drive and your games on another.

Size:37.1 x 12.8 x 20.4 cm
Weight:5.42 kilograms
Power:550 watts

4. Sonnet eGPU Breakaway Puck RX 5500 XT

The Sonnet eGPU Breakaway Puck RX 5500 XT is a really tiny thing among the external graphics cards. And it is a special tiny thing: the other solutions all come without a graphics card. The AMD RX 5500 XT is integrated with the Breakaway Puck. Accordingly, the external graphics card is aimed at users of a Mac Mini or MacBook who want to give their computers a little more graphics power. But they shouldn’t expect too much performance: The AMD RX 5500 XT is one of the manufacturer’s entry-level cards. For gaming enjoyment without compromise in Full HD resolution, more power is a must. 

Size: 7.5 x 3.1 x 15.5 centimeters
Weight:1.5 kilograms

You can also read: How to Remove and Apply Thermal Paste on CPU

External graphics card: the disadvantages

Passionate PC gamers know: Gambling on a laptop can only be a stopgap solution. Compared to a desktop, the notebook hardware is simply left behind. It simply has to do with the nature of foldable computers and hardware. Powerful graphics cards are big and use a lot of power. And the more electricity the hardware consumes, the more heat it generates that needs to be cooled down. 

Both speak against the self-image of a laptop. It should be as light and energy-efficient as possible so that its user can work on it for as long as possible on the go. Most flat devices simply do not offer space for large fans that cool the graphics card. Not even when manufacturers call their laptops all sorts of “gaming” tricks – the notebooks do not come close to a desktop.

The eGPU does not change anything about that. Why? It is related to the data throughput of Thunderbolt 3. In theory, the interface lets through a maximum of 40 gigabytes of data per second, which is sufficient for a graphics card to develop its full performance – but only in theory. In practice, the 40 gigabytes per second are divided into different channels. 

You can use the Thunderbolt connection with an appropriate dongle to manage different types of transmission at the same time. That would be an Ethernet cable or USB-C devices like an external hard drive, mouse and keyboard, or multiple monitors. The data throughput for PCIe connections such as graphics cards is falling accordingly. And that is exactly what can throttle the performance of the eGPU.  

Is it even worth buying an external graphics card?

With the prices for the housing and graphics card, it is questionable whether the purchase of an external graphics card is worthwhile because at around $300 the housings are not exactly cheap – especially when you consider that the graphics cards may not be able to exploit their full potential. Alternatively, you could also build a gaming PC yourself. But wouldn’t that be many times more expensive?

Inexpensive PC case cost around 70 dollars, a decent manufacturer around $100. Also, there are $100 for 16 gigabytes of RAM, 100 dollars for the mainboard, about 200 dollars for a processor like the Ryzen 5 3600X, and around $50 for a small SSD. For a full-fledged desktop (without graphics card), you spend around $320 more – and get the full performance of the graphics card and, with a high probability, more processor performance. And it could perhaps save the additional costs by using a less powerful laptop. 

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