Like many people today, I use my laptop constantly. It goes with me as I move from office to office at work, go home for the evening, stop by the coffee shop, and travel both nearby and around the world. This means I care about system durability and battery life, but I also need excellent performance.

At Principled Technologies, we recently tested four Microsoft Windows 7 laptops for Dell—the Dell Latitude E5420, the Dell Latitude E6420, the HP EliteBook 8460p, and the Lenovo ThinkPad T420. The bottom line was that the two Dell laptops proved more durable and had better battery life than the others, while delivering comparable performance.

Both Dell laptops withstood three 29-inch-high drops that severely damaged or killed the other systems after only one fall. While none of us plans to drop our computer, accidents happen—it’s reassuring to know your system can stand up to such an event. The Dell Latitude E5420 and E6420 batteries also lasted longer than the competition’s batteries—by as much as 18.2 percent, or an entire hour of working time.

To look at the laptops’ performance, we conducted two benchmark tests. On BAPCo SYSmark 2007 Preview v1.06 (a measure of overall system performance on common business applications and tasks), all four systems showed comparable performance, likely because they have the same processor. On Futuremark 3DMark Vantage 1.1.0 (a measure of 3D graphics performance), the Dell Latitude E6420, which features both integrated and discrete graphics, earned a score of 2,397, better than the HP EliteBook 8640p score of 1,916 and comparable to the Lenovo ThinkPad T420 score of 2,523. With a 3DMark score of 1,776, the Dell Latitude E5420, which has only integrated graphics, wasn't far behind.

Having your laptop battery die before you’ve completed your work is frustrating; losing your entire system—and any work you haven’t backed up—due to an accidental fall can be very costly. Choosing the Dell Latitude E5420 or E6420 can help you avoid both of these outcomes without sacrificing performance.

For more details, check out our full report.