In our environment the missing "TDirectoryCache" of the FixPack seems to be the main blocker. We have reported this issues already middle of Sept (https://quality.embarcadero.com/browse/RSP-21972, https://quality.embarcadero.com/browse/RSP-22289). It was reproduced by EMBT but nothing happened until now.
IMO a fixpack with only this feature would improve the speed already a lot for larger projects and solves the problem of the IDE freezes we do have.
I asked EMBT several times to include such a cache into the SP1 of RIO. But no commitment yet.