Research is key here. For powder boards, the main objective is to keep the board afloat--keeping tip up. First thing I would look at is make sure the tail is skinnier than the tip. if the tail and tip are same width--its not a powder board. Most powder boards are about 2 centimeters more narrow. The idea is to make the back end sink a bit. Plus camber boards don't do quite as well as hybrids. Hybrids do better in powder.
As long as the board has these 2 features, it will make a good powder board. You can find boards that do powder and all mountain very well.
So when doing your research look for those 2 key things.