Antialiasing of matte objects

[zargan]

hi,

i have got a problem with matte objects. Vray seems to antialiase them, so my scene rendering slows down when the renderbucket hits certain matte objects (like xfrog plants). I was able to speed it up by giving these obejcts a vray material wrapper (matte on). Is there a solution for that?
It really seems to be an antialisasing prob, as i can also speed it up by using lower AA settings.

thanks