iskan Why did you decide to kill the Mantra (replace)? Will a video card work in Karma? How much does speed differ from Renshift?
Goat doesn't speak for SideFX, and neither do I. I think it was a bit of a hyperbole.
I like to think of Karma as Mantra 2.0, but smartly the SideFX team isn't getting rid of it until Karma is fully 100% production ready, which I suspect it won't be in this release.
Karma is not GPU-based, at least not yet. There are enough hints which lead us to believe it might be in the future, but right now it's 100% CPU (like Renderman).
Regarding speed comparisons with Redshift, we'll need to wait until it's in our hands. I suspect it won't be as fast as Redshift for most things, but in some things it might be. Even Mantra can be faster than Redshift for certain things like volumetrics for instance.