Dell accidentally lists laptop over an inch smaller, promises to fix the error soon
Dimensions and weight can be tricky to nail down for laptops and this is especially true for mobile workstations where a very wide range of SKUs and storage solutions are often available. We wouldn't hold it to any manufacturer if measurements were off by several grams or a fraction of a millimeter, but we can certainly be suspicious of measurements more than 10 mm or even 20 mm shorter than in reality.
As of this writing, the official product page for the 15.6-inch Dell Precision 7530 is listing the workstation as only 337.6 mm (13.29 inches) wide. In comparison, even the latest XPS 15 9570 is wider at 357 mm and it has one of the narrowest bezels for its size class. It's likely just a listing error rather than a marketing exaggeration since a quick look at the official user's manual for the Precision 7530 shows a longer width of 377.6 mm (14.87 inches) instead.
We've contacted Dell who was quick to confirm that this is indeed an error and that the product specifications will be updated accordingly to a width of 375.92 mm (14.80 inches). Other than this faux pas, the Precision 7530 is still smaller than the Precision 7510 that it replaces and it one of the very few workstations in its size class to support both Core i9 and 128 GB RAM options. We recommend checking out our review of the Precision 7530 for more information on the system.