Intel has ruled the market for central processing units since the 1980s. But rival AMD overtook Intel in market value last year, thanks in part to an expensive bet on chip design. WSJ’s Asa Fitch explains the companies’ battle for the brains of your computer. News Explainers Some days the high-speed news cycle can bring more questions than answers. WSJ’s news explainers break down the day's biggest stories into bite-size pieces to help you make sense of the news. #AMD #Intel #WSJ