stock

I have been using the stock Black and White patch to render any photo/video in BNW, however, this seems to be very costly to the CPU when used in a live video sense. Iw as wondering if there were any more effective ways to render a image source Black and White?

When I switch to BNW now I lose easily 50% of the frame rate and I know there must be a better way to do this. Any suggestions are much appreciated!