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Old 28 June 2015, 20:42   #12
Toni Wilen
WinUAE developer
Join Date: Aug 2001
Location: Hämeenlinna/Finland
Age: 41
Posts: 17,857
Originally Posted by BarryB View Post
Plus SCSI uses much less CPU time.
This is popular opinion but it is not really true (in Amiga world). Only SCSI with DMA controller uses less CPU time than PIO IDE. There is at least over 30 different SCSI controller models for the Amiga and very few are true DMA, especially pre-Z3 models. Most are PIO = they are as CPU power hungry as Amiga IDE controllers. (I was also surprised, I expected more true DMA models. I noticed it when I started adding 3rd party SCSI and IDE controller emulations)

IDE + DMA controller would be more or less equal to SCSI + DMA controller in CPU time usage.

AFAIK problem with DMA controllers is that it is really difficult to make it work (and work fast) with all kinds of expansion devices and different main board versions. Should be more possible now that all chips and whole board is guaranteed to same.
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