Benchmarks, and recommendation on when the i9 is worth it for cost when both have a Vega 20 (spoiler - short intense calculation, the i9 is worth it, long running applications, i7 is almost the same performance)
https://appleinsider.com/articles/1...hz-i7-versus-the-29ghz-i7-vega-20-macbook-pro
https://appleinsider.com/articles/1...hz-i7-versus-the-29ghz-i7-vega-20-macbook-pro