What it is: Blackmagic sells an external graphical processor unit that connects to a laptop through a Thunderbolt port.
In the old days, a single processor did everything. Then for improved graphics, computers started including graphical processors. Nvidia is the most popular maker of graphical processors but AMD and even Intel makes them as well.
With desktop computers, you can swap graphical processors in and out through expansion slots, but with laptops, you can’t. That’s why Blackmagic sells an external graphical processor that connects to a laptop through a Thunderbolt port. This gives a laptop the graphical processing power of a desktop PC. The moment you take the laptop on the road, you’re stuck using whatever graphical processor the laptop might offer, but when you get back to your home or office, you can rely on the external Blackmagic graphical processor.
The Blackmagic external graphical processor isn’t cheap ($699), nor is it upgradeable so you’re stuck with the graphical processor built inside the Blackmagic unit. External graphical processors may be handy for professional users who don’t want to use both a laptop and a desktop when they can rely on a single powerful laptop instead. If you’re a video professional, gamer, or other user who demands the best graphical processor possible for a laptop when sitting at a desk, then the Blackmagic external graphical processor may be for you.
For everyone else, external graphical processors are interesting but not necessary. We’ll just limp along with the built-in graphical processors in laptops and be content with that. An external graphical processor isn’t as handy as expansion slots in a desktop computer, but at least it gives you an option to increase your laptop’s graphical processor if you really need to.