3600Mhz is ideal in that is should be easy to achieve in 99% of cases as long as your memory isn't bad.
3800 with 1900FCLK gives best performance instead. But not all motherboards and cpu:s can handle the 1900FCLK. There are cases when even 1800FCLK wasn't stable for some rare cases but most should be able to do 1800FCLK to match the 3600Mhz MEM speed.
That is unless you run 4xDR memory for 64GB etc which can limit your max clock to some extent. Seen people struggle with that to some extent.
Gigabyte X570 AORUS XTREME, Ryzen 7 3800X 4.4Ghz, 4266/1900 MEM/FCLK, 18.104.22.168.76.tRFC 650 1T 1.600V
4x8Gb Kingston HX434C19FB2K2/16 3466C19 1.2V (Micron E-die 16nm)
OLD: Biostar x470GT8 Ryzen 7 1700 @ ~4.0Ghz CPU, 3200Mhz RAM ...