What would be the easiest way of veryfying whether two binary files are the same, without actually opening them, checking versions and such in different programs ... ?

I primary mean files like 3d models, acad drawings, and the like, of which I have different versions, saved in different directories, and upon completing, I just want to find which are the newest, and which are different from the newest, and delete every other.

So far I've thought od md5 ? Any other ideas ?

This doesn't actually fit under "diff" tag so feel free to change it, if you can think of a better alternative.