ps3 and pc are working PERFECTLY fine with a cat5 cable (no it's not a crossover).
Do you know what is crossover? It is as you said CAT5 cable
There are two types of CATx cabling(depending on termination of these cables):
Modern network cards/switches supports Automatic MDI/MDI-X so in other words you can use any CAT cable and it will work.
So maybe you are not using crossover, maybe it is straight-through cable but it is CATx cabling