I see this all the time on Lumia 928 with latest updates. It's extremely annoying and going to push me away from windows phone. I absolutely love the design and the live tiles, but is it worth all the frustrations from the OS? Any time I've used the latest iPhone, everything seems to work seamlessly and smooth. Can't say I ever had that on my 928.
Also, for those debating the hard reset. I've done it and it didn't help whatsoever.
Just a couple of points - I suspect that you are running Preview software so you need to recognize that when comparing to another OS.
Also with regards to a hard reset - did you restore from a backup or perform a completely clean install of all your apps?