AMD has moved from 23 to 32% desktop market share between Q2 and Q3 of 2019, while Intel has fallen from 76 to 68% during the same time period. This is clearly a zero-sum game, where a win for AMD is a loss for Intel. This article offers an explaination for why AMD has been able to take market share away from Intel on the desktop [CPU]. Bottom line, it is all about the transistor budget and the design rule.
Lyon, Douglas A.
"The Rise of Ryzen,"
International Journal of Computer and Systems Engineering: Vol. 1:
1, Article 1.
Available at: https://digitalcommons.fairfield.edu/ijcase/vol1/iss1/1