Question on Amiga HD controllers

[kolla]

You are correct, the bottle necks are the controllers. Paging to disk (swapping) works well on SCSI systems, and there are SCSI-to-SATA adapters that can work much faster than any SCSI controller on any Amiga manage. I have replaced all my PATA drivers with SD-card adapters and mSATA-adapters lately.

ACard provide SCSI-SATA adapters:
http://www.acard.com/english/fb0101.jsp?ino=43&sino=45

[kolla]

The fastest SCSI controllers are hands down those located on the accelerator boards, such as the NCR 53C770 based UW controllers on the CyberStorm boards, much faster than working over Zorro bus.

I have used swapping (http://aminet.net/package/util/misc/VMM_V3_3a) quite a lot, mostly when working with animations and sound.