Why C10 and C9.5 twice slower that 8.5

Although I do love Cubase, sometimes I fail to understand why new versions work slower than previous ones?

Checked track render in C8.5 , 9.5 and 10 - 9 and 10 took almost twice longer to render.Same project, same plugins, same everything except for the render time! Stenberg WTF?

BTW, I’ve recently upgraded my computer to Intel i9 Extreme core with 18 cores and 64GB of RAM, but didn’t get the impression that this configuration works somehow faster than my previous i7 with 4 cores. Does Cubase utilize all available resources as it should?