Dell XPS 13 (2015)
Updated with a 6th-generation Intel Core i5-6200U processor, 8GB of RAM and a 256GB SSD, the latest generation of the XPS 13 will cruise through pretty much anything. I streamed two movies at the same time and churned through a big spreadsheet without noticing any performance hit.
On Geekbench, which measures overall performance, the XPS 13's score of 6,391 topped the Yoga 900 (6,264), despite that notebook having an Intel Core i7-6500U CPU, 16GB of RAM and a 512GB SSD. The MacBook Air, which runs a 5th-generation Core i5 processor, scored 5,784.
Despite its high score on synthetic tests, the Dell fell behind both the Mac and the Lenovo on our spreadsheet test. Its time of 4 minutes and 34 seconds, to pair 20,000 names and addresses in OpenOffice, was slower than the Yoga 900 (4:18) and the Apple (4:03).
In duplicating 4.97GB of multimedia, the Dell's hard drive speed of 231 MBps proved faster than the Yoga by about 50 MBps, but slower than the Air's flash memory by 127 MBps.