Apple introduced a $700 device on Thursday called an "eGPU," made by a company called Blackmagic, that can give a 13-inch MacBook Pro better performance than any 15-inch MacBook Pro that Apple sells.

An eGPU is an enclosure that houses a graphics card, and you can plug it into a MacBook Pro with a USB-C cable, just like you would plug in your laptop's charger.

Apple's 13-inch MacBook Pros don't come with graphics card, which are useful for power-hungry tasks, like photo and video editing, as well as playing games. That's a privilege reserved for the 15-inch models. Adding an eGPU to the 13-inch MacBook Pro helps bridge the performance gap with the 15-inch models.

Plugging in the Blackmagic eGPU to the 13-inch MacBook Pro would actually give you much better performance than any 15-inch MacBook Pro that Apple sells. The Blackmagic eGPU comes with an AMD Radeon RX 580 graphics card, which is significantly more powerful than the Radeon RX 560x that's in the high-end 2018 MacBook Pro.

It also means you get the portability of a 13-inch laptop with the option of adding the performance of a larger laptop, or even a full-size desktop.

The thing is, there are already other eGPU options made by a company called Gigabyte that are cheaper for the exact same performance. Some even offer better performance for less or the same price as the Blackmagic eGPU.

Check them out: