it should be at least 3 times faster from what people have stated, because even the 800mhz processor in the upcoming samsung phone is not nearly as fast as the A8 @550.
also, the chipset has a seperate GPU which should handle all the rendering, freeing up the CPU cycles for even more other processing.
people have said it would be close to if not on par with the 1Ghz Snapdragon chips, but we'll see once one of those get out into the real world