[mikepurvis]

I had a P4 (~1.6GHz) at one point and I remember DVD playback even on that system was a bit flaky. Like it was mostly good but would hitch for a second or two every fifteen minutes. Just often enough to make it pretty annoying for trying to actually watch a full movie.

[AnotherGoodName]

If you were still in that era i'd say make sure the drive is in DMA and not PIO mode!

The drives would operate in a fallback mode called PIO unless you installed specific drivers for the DVD drive. The symptoms you describe sound like this. 1.6Ghz was definitely enough for MPEG2 decoding.