Re: I played PVZ GW have only 30 fps,sometimes even lower.

Read through this thread:

http://answers.ea.com/t5/PvZ-Garden-Warfare-PC/This-game-is-not-support-2-GPU-Graphic-card/m-p/3077514/highlight/true#M1824

I gave it my best shot at doing it through software... I did it blind without one of these cards to play with.

Borderless mode should only use a single GPU... not the best solution IMO especially if it's possible to get it disabled fullscreen.