From my early testing thus far of the Linux 6.6 kernel in its very early state, some of the most impressive gains are happening on AMD's high core count server processors, the EPYC 9754 'Bergamo' in particular is enjoying some stellar improvements for various server workloads on this forthcoming kernel.
Following the release of Linux 6.6-rc1, now that the merge window is over like usual it's a matter of beginning to test the new kernel code on a range of hardware.