As a general rule of thumb, if there are two similar GPUs from the same line (i.e. an NVIDIA GTX 260 vs a NVIDIA GTX 280), will the less powerful or more powerful GPU run hotter? This is assuming all other factors stay the same - hardware configuration, cooling setup, ingame settings, etc.

Or does this depend entirely upon the GPU itself? I do remember reading that the GTX 280 in this example was terribly inefficient with power and cooling.