Optimal hardrive speed in my A1200 / 030 RBM busboard

[Zac67]

The 53CF94 can do Fast SCSI w/ DMA. RAM speed shouldn't be a problem, so 10 MB/s should be realistic, depending on the harddisk. Accelerator SCSI is always the fastest option.

From the manual:

The two checkboxes "Synchron" and "Reselection" allow you to specify that a
hard  disk  or  another  SCSI  device  is to be automatically switched into
Synchronous  or  Reselection mode at system start-up.  You can change these
settings  and  store  the  changes  in  the  main window without losing the
existing  data.   For  the meanings and advantages and disadvantages of the
operation modes, please read the description of UnitControl.

[Zac67]

The speed doubled with that set though I have to disable it if I Plug an external CD Drive in.

Crappy cabling or termination...

[Zac67]

... and you do remove termination on the Blizzard and add it to the external drive, don't you? Active terminators?
Fast SCSI can run for 3m in total and if it doesn't there's something wrong.

[Zac67]

Have you tried forcing it off? Or another cable?