Well GPU manufacturers aside, if a coin can be mined much more faster on nvidia cards than AMD
how is 11 MHash/s (780Ti stock) to 9 MHash/s (R9 290 OC) "much faster".
okay, we're not done with optimization yet, but I think you're overdramatizing this.
I just don't know what you have cooking for nvidia so I assume the worst, but I agree slight hash differences has no effect in the long run.