This fall, Nvidia will officially become a consumer PC chipmaker like Intel, AMD, Apple, and Qualcomm, putting a complete computing chip — not just graphics — into the very heart of laptops and mini-PCs. After many months of leaks, it’s finally announcing the RTX Spark, the first in a family of chips that will meet or beat the most powerful thin-and-light Windows machines ever, it claims.“This is the most efficient PC chip ever built,” says Nvidia senior director of product management Mark Aever...