Never believe that if a review says the load temps are 56C, your particular card will have 56C load temps. It's probably a cherry picked sample that is sent to the review - your load temps might be 20C higher. It depends so much on the particular chip - it's a well known fact that operating voltage varies in different units of the same model (and that's not even the only contributing factor; different chips will have different temperatures with the same voltage and MHz). If a unit fits the requirement of being stable, then it can be sold, there is no guarantee of low load temperatures.
Case in point, Guru3D and some other review sites found load temperatures as low as ~60C for the Gigabyte GTX 560 Ti Super Overclock, the 1000Mhz version released first. My particular chip runs at about 80C with the default fan profile, and in certain conditions (low case airflow) it will be unstable at that factory OC. Hence I run it at 960Mhz and 0.1V less, stays a lot cooler even with a quieter fan profile.
I'm still convinced this DualX is a perfectly normal double slot, dual fan cooler. There's just not many ways you can improve on that design. The main things that determine how well a cooler works are (1) airflow i.e. the fans and their RPM, and (2) heatsink size and fin area. It's not rocket science. If you want to make a truly better cooler, add more fans (Gigabyte's triple fan cooler) or increase heatsink size (Asus' triple-slot DCII). Or both (Arctic Cooling Accelero Xtreme).