If that's your only option. Stick with ribbon (flat) IDE cables.
Note on the rounded cable, shielding does not go all the way upto the connector. A failing with most round cables, which must be shielded in order to be of any true benefit. Whether it's worth the cost is another thing.
Typically excellent ribbon 80wire/40pin cost in the UK less than Â£2.
Typically excellent round cable 80/40pin cost in the UK is likely to be at least five times that.