The whole point of having 2x the number of wires you need is so that you can use every other one and get a much clearer signal. Folding the wires together so they are all more or less in a bunch partially defeats this. Although I really am interested in improving my case airflow, it is more important that I'm not getting bad signal degradation over the IDE cables, so I do not, and would recommend against folding them (cutting them and tieing them together is also less than ideal).