I converted main partition on hard disk to APFS and now it's very slow. I know I shouldn't use it on hard disks, but installer (which updates 10.12 to 10.13) c

I converted main partition on hard disk to APFS and now it's very slow. I know I shouldn't use it on hard disks, but installer (which updates 10.12 to 10.13) crashed otherwise, leaving system unbootable (booting to installer again). After converting root partition to APFS installer was able to complete installation. Not sure, however, that APFS is the reason of slowdown, maybe other filesystems are slow too in this version. FS cache, however, still works, and after warmup system becomes fairly responsive (on 16 Gb of RAM).