Founders cards being worse than board partner models hasn't been true in like 8 years. They switched to dual axial rather than a single blower fan with the 20 series, which made the value of board partner models hard to justify.
Since then, Nvidia is locked in a very strange card war with their board partners, because Nvidia has all the juicy inside details on their own chips which they can just not give the same treatment to their partners, stacking the deck for themselves.
Also, the reason why blowers are bad is because the design can't really take advantage of a whole lot of surface area offered by the fins. There's often zero heat pipes spreading the heat evenly in all directions, allowing a hot spot to form.
