I'm personally sick of hearing this sabotage excuse used left and right. The whole Batman ant aliasing issue isn't without merit, but insofar as game performance on comparable in game features, I HIGHLY, and I mean HIGHLY doubt a dev is "sabotaging" their game's performance for the sake of nvidia.
The TWIMTBP program involves sending nvidia engineers to help the dev code the game to run fastest on their hardware, not to sabotage the performance of the game on other hardware. If AMD were as marketing savvy and as smart as nvidia, they'd implement similar programs.
Somehow the sabotage makes sense. Good example of this;
1 - Lost Planet - When the game was released, it was a direct port of the Xbox 360 which uses ATi hardware, the game usually ran almost twice as slower with ATi hardware than nVidia hardware, how could that be possible? Is a game that isn't that challenging regarding in graphics, why? nVidia hardware is usually faster in texture filtering and with considerably amounts of simple shaders with lots of dependant texture reads, while ATi hardware its much faster with lots of very long mathematical shader instructions. The game was coded in nVidia's way that favores it and hampers the performance in ATi hardware.
2 - Deadspace - The same thing, the game while runs over 100 - 120fps in HD 48x0 series, the GTX 2x0 series smokes it with over 160+, but why? The game doesn't look that great compared to other games like Crysis which runs comparable on both vendors, why?
3 - Batman AA - Anti Aliasing disabled in the in-game options, why? Mirrors Edge uses the same identical engine and offers in-game Anti Aliasing options with both vendors, why Batman AA couldn't? Are EIDOS developers that lousy?
4 - Cryostasis - They even had to release a patch to fix issues with SM 4.0 and ATi hardware, why? If they were supposed to follow the DX spec carefully, it wouldn't happen.
If you want it, search for the reviews of those games when they were launched and you will see what I mean. Is true that ATi architecture is quite dependant of driver optimizations to increase efficiency, but those cases are quite ridiculous.