Cadillac XT5 vs Porsche Cayenne: Specs Compared

Running cost over five years: at the EPA's 15,000-mile-a-year assumption the Cadillac XT5 burns about $2,800 of fuel annually against $3,300 for the Porsche Cayenne. That $500 yearly gap compounds to roughly $2,500 over five years and $4,000 over eight — often more than the price difference between two trims of the same vehicle, and the single largest running-cost line item separating these two.

City versus highway split: the Cadillac XT5 is the stronger commuter at 22 mpg city, while the Porsche Cayenne pulls ahead on the interstate at 29 mpg highway. If most of your driving is stop-and-go traffic the city figure is the one to weigh; for long-distance highway mileage the reverse is true, and the two vehicles effectively swap places depending on how you drive.

Powertrain choice: the Cadillac XT5 is recorded with 1 distinct engine configuration (SIDI), the Porsche Cayenne with 4 (SIDI, SIDI; PHEV, 4.0). Across 50 recorded Cadillac XT5 configurations and 97 for the Porsche Cayenne, the wider the engine spread the more the real-world fuel efficiency depends on which version you actually buy, so check the specific model year and drivetrain rather than the headline number.

Drivetrain and class: the Cadillac XT5 is offered with All-Wheel Drive, Front-Wheel Drive, the Porsche Cayenne with All-Wheel Drive. All-wheel drive typically costs one to two mpg combined against the same vehicle in front- or rear-wheel drive, which is worth remembering when the gap between these two is small. The EPA classes them as Small Sport Utility Vehicle 4WD and Standard Sport Utility Vehicle 4WD respectively — the class drives the interior volume, cargo space and passenger space each one is measured against.

Tailpipe emissions: at their cleanest configurations the Porsche Cayenne emits 174 g/mile of CO2 versus 363 g/mile for the Cadillac XT5. Emissions track fuel consumption almost exactly, so the cleaner vehicle here is also the cheaper one to fuel.