As my two pcs are low/medium specs, I just tested in notebook (the lower specs) setting "-FPSLimit=20" (steam >properties > set launch options), and I got stable 19-20 FPS (TSX OFF). Keeping the Steam settings (20FPS), if I choose now TS2012 command line "30FPS Lock" the FPS may raise till 30 FPS, when is the rare case. It means that TS2012 command line checked (30 FPS) overrides the Steam setting (20 FPS). If I uncheck 30FPS Lock, the limit goes back to Steam option (20FPS).
What I'm not really understanding is why CPU usage (Dual Core) drops from average 55-60% (TSX OFF, 20 FPS) to 25-30% when I turn TSX ON (10-12FPS)!!!!

Looks like the FPS dropped 50%, because cpu usage dropped 50%! Or should be the opposite?! I'm reporting this odd issue to Support....
Who doesn't have dog, hunts with cat.