qB not uses RAM cache on Synology NAS

[Bonza]

Hello, i trying to ease job for hdd by pushing qB to use RAM cache but it doesn't work at all.
Read and Write cache hits always show zero, Disable\Enable OS cache seems not do anything. I was using some Chinese version directly from Package Center and other one from linuxserver in Docker. Both behave the same. So i don't know it is syno or qb problem.