i also experience similar behaviour.
while photoshop CC 2014.1.0 works very smooth on my Mac Pro (late 2013), sometimes it gets rally sluggish for few seconds, i can't do anything, no zoom, no brush.
i don't need to switch the applications, it just gets normal after a while.
it happens randomly but quite often. maybe each 10 minutes.
i checked the activity monitor, but nothing remarkable there.
running OSX 10.9.5, i experienced the same behaviour also under 10.9.4 too.
thanks for any advise.