Hi. I have the Note 3 and my KNOX=0x1. As far as I know it has no effect on performance however it could effect warranty. Mine was set off when I rooted it. As kangal mentioned there are new ways to root such that it will not blow the KNOX efuse. So if you are more patient than me you might wait/check to see what is available for rooting Note 2. Also, as I understand this, it is not a hardware type fuse but software related although, last I checked, no one knows (outside Samsung and some phone companies) how to reset it. So at this point you can have stock and root and keep KNOX=0X0 but once you try out other roms you will trigger KNOX. BTW, if anyone is deciding between Note 2 and Note 3 definitely go for Note 3. It is has superior screen, cpu, memory, much quicker charge up, lots of nice new features. Also many aspects of multiwindows has been further improved by developers on XDA.