It's all on google.com but in short, ATA33 is a SPEED of the clock rate of the data. At 33MHz, the old 40 conductor cables worked fine.
At 66MHz the NEW 80 CONDUCTOR cables were needed to improve the signal quality.
DMA was implemented and kept from long ago so it's not a factor of ATA33/66 speeds.
Bob
could somebody tell me what the difference between ATA33 and ATA66 is please? is it the number of connector pins, the number of wires , DMA support or the blue connector? It might just be that I'm thick!

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