If you spend some time perusing forums like NotebookReview or reddit these days, one of the most common questions you'll see being asked over and over is "What is the best laptop to use with an external GPU?". The reason it's still being asked is that there still isn't a perfect all-around laptop yet: Ultrabooks are portable and sleek but have low-powered 2 core/2 thread CPUs that will bottleneck powerful cards and will be unable to run some games well, even with a GTX 1080 attached. There are quite a few gaming notebooks with quad-core CPUs and the necessary Thunderbolt 3 port, but they are often big, heavy, or have gaudy, toy-like designs. The Dell XPS 15 with its quad-core CPU, sophisticated design, and light weight would be at the front of the pack here but for one thing—its TB3 connection is limited to roughly half-speed (16Gbps) when used for eGPUs, meaning it will not have the bandwidth to power games on the internal screen properly.
This is where the new Latitude 5840 steps in. A 14" laptop business laptop weighing just 3.52 lbs and measuring 0.9" x 13.1" x 9", the Latitude 5840 still packs up to an i7-7820HQ processor and a full-speed TB3 port, making it a great choice for someone wanting a compact-yet-powerful computer that is well-built and does not look like a toy. Even better, as the Latitude is a business notebook, it packs every security and connectivity option you might want: a SIM card, WWAN, WiGig, IR camera, fingerprint scanner, smartcard reader, and touchscreen are all options. The icing on the cake (for me, anyway) is the optional trackpoint.
If there are any downsides to the 5840, its that the i7-7820HQ model requires the inclusion of a Geforce 930MX (a low-end GPU that is barely faster than the integrated HD 630 graphics, and will just waste battery when in use) and that its screen and bezels don't compare to the XPS line. It also isn't cheap as configured—when configured to my liking, the price was slightly north of US$1800. Still, a very solid 3-year warranty comes standard here along with that price tag.
If you're looking for a compact, powerful, and well-built device that can be taken anywhere and gamed with at home, give the Latitude 5840 a good look. Just don't buy an Asus ROG XG Station 2 as your external graphics card enclosure—it won't work with it until Dell certifies their laptops for eGPU use. Stick with an AKiTiO Node or Razer Core to ensure compatibility for the time being.