Originally Posted by matthey
Do you know which few Amiga HD controllers are DMA? I believe the CSMK3/CSPPC is. Perhaps the 3000 and 4000T SCSI as well?
24-bit DMA (Zorro-2/A500):
- All GVP Series II and any GVP combo accelerator that includes Series II SCSI (Series I is not true DMA)
- Commodore A590, A2091 (A2090 is also DMA but it has issues)
- Masoboshi MasterCard (DMA implementation quality is unknown). This is also IDE DMA capable. Possibly the only Amiga IDE DMA controller!
- (SupraDrive 2000 non-WordSync is DMA but it had bad implementation)
- Phase 5 SCSI controllers (Blizzards and CyberStorms, FastLane)
- GVP combo accelerators based on 32-bit upgraded Series II DMA controller.
- WarpEngine (missed this. 53cxxx)
All SCSI controllers based on 53C7xx, 53C8xx are always true DMA. DMA controller is chip built-in. (A4000T, CSPPC etc..)
DMA does not have any "native" speed limit, it is controller, interface and memory bandwidth specific. EDIT: CPU upgrades rarely increase DMA controller speed because limit is DMA controller hardware, not CPU. (vs PIO controllers).