Fusion Drive High Sierra to Mojave Slow-w-w-w now

[steveonmac]

Hi, I upgraded my iMac from High Sierra (HFS+) to Mojave (APFS). Now it’s so slow it’s unusable. Right now, I’ve booted from an external drive with High Sierra. Anyone comment on where to go from here? My specs: Fusion drive iMac "Core i7" 3.5 27" (Late 2013) Identifier 14,2. Thanks.
/dev/disk0 (internal, physical):
#: TYPE NAME SIZE IDENTIFIER
0: GUID_partition_scheme *121.3 GB disk0
1: EFI EFI 209.7 MB disk0s1
2: Apple_APFS Container disk3 121.1 GB disk0s2

/dev/disk1 (external, physical):
#: TYPE NAME SIZE IDENTIFIER
0: GUID_partition_scheme *5.0 TB disk1
1: EFI EFI 209.7 MB disk1s1
2: Apple_HFS 2 - LACIE 5 TB EXT 5.0 TB disk1s2

/dev/disk2 (internal, physical):
#: TYPE NAME SIZE IDENTIFIER
0: GUID_partition_scheme *3.0 TB disk2
1: EFI EFI 209.7 MB disk2s1
2: Apple_APFS Container disk3 3.0 TB disk2s2

/dev/disk3 (synthesized):
#: TYPE NAME SIZE IDENTIFIER
0: APFS Container Scheme - +3.1 TB disk3
Physical Stores disk0s2, disk2s2
1: APFS Volume HARD DRIVE 2.2 TB disk3s1
2: APFS Volume Preboot 45.0 MB disk3s2
3: APFS Volume Recovery 510.4 MB disk3s3
4: APFS Volume VM 2.1 GB disk3s4

 

[shorty135]

Hi, I upgraded my iMac from High Sierra (HFS+) to Mojave (APFS). Now it’s so slow it’s unusable. Right now, I’ve booted from an external drive with High Sierra. Anyone comment on where to go from here? My specs: Fusion drive iMac "Core i7" 3.5 27" (Late 2013) Identifier 14,2. Thanks.
/dev/disk0 (internal, physical):
#: TYPE NAME SIZE IDENTIFIER
0: GUID_partition_scheme *121.3 GB disk0
1: EFI EFI 209.7 MB disk0s1
2: Apple_APFS Container disk3 121.1 GB disk0s2

/dev/disk1 (external, physical):
#: TYPE NAME SIZE IDENTIFIER
0: GUID_partition_scheme *5.0 TB disk1
1: EFI EFI 209.7 MB disk1s1
2: Apple_HFS 2 - LACIE 5 TB EXT 5.0 TB disk1s2

/dev/disk2 (internal, physical):
#: TYPE NAME SIZE IDENTIFIER
0: GUID_partition_scheme *3.0 TB disk2
1: EFI EFI 209.7 MB disk2s1
2: Apple_APFS Container disk3 3.0 TB disk2s2

/dev/disk3 (synthesized):
#: TYPE NAME SIZE IDENTIFIER
0: APFS Container Scheme - +3.1 TB disk3
Physical Stores disk0s2, disk2s2
1: APFS Volume HARD DRIVE 2.2 TB disk3s1
2: APFS Volume Preboot 45.0 MB disk3s2
3: APFS Volume Recovery 510.4 MB disk3s3
4: APFS Volume VM 2.1 GB disk3s4

On another forum, someone said that if you are running High Sierra and above, you should use APFS. The person also said that APFS format is optimized for SSD. I asked if I can run Mojave on an external hard drive formatted as APFS. The person said that it would run slowly.