Not sure if this is tripping any of you guys up but xintensity 64 for a 290x is not the same as xintensity 64 for a 280x or even a 290. xintensity is a multiple of shaders your card has.
For example a 290x at xintensity 64 is 2816*64 = 180224 raw intensity which is close to an intensity of 17.45 (2^17.45 = 179049)
a 290 at xintensity 64 is 2560*64 = 163840 raw intensity which is close to an intensity of 17.32 (2^17.32 = 163621)
Not much of a difference between a 290x and a 290 but with a 7950 having 1792 shaders would be something like an intensity of 16.8
Again not a huge deal but something to consider.
No shit. That's the entire point of xintensity.