My G5 1.8 dual has a newly installed Toshiba 1TB hdd.
Downloading (anything from anywhere) to the SFS partition is really slow, the previous WD 750GB hdd has no problem.

Changing the SFS settings in MorphOS Preferences resolved this.
Move the default value "Read-ahead Buffer:" to the maximum.

The same with the G4 MDD (Seagate 250GB), which also had a slow download to the SFS partition.

Is it a "hard drive case" or a "Wayfarer case"?

OWB downloads at full speed before and after changing SFS settings.