Hello there, SAME problem here.....installed yosemite and first of all, the hand tool is a little lag....I mean, no soft panning....but I can live somehow with that..... the really messy problem is that, when I use any tool or perform any action, (zoom, rotate, whatever), sometimes photoshop catch it instantaneously, and some other times it has a little BUT ANNOYING lag just at the moment you use it... being the most frustrating situation with the brush....sometimes I make a stroke and is ok and when I make the next stroke, photoshop draw the line like, half a second later...which is FRUSTRATING AS HELL (sorry I have spent all evening trying to solve the issue so I am frustrated), but the most weird thing is that sometimes JUST sometimes when I open photoshop...suddenly the problem disappears and everything is soft and perfect (even the hand/ panning tool)....but after working for some hours the problem randomly appears again....I thought it was the driver ....but no i think is not.... I tried downloading the old one and stuff but I think is a problem of photoshop and yosemite .....because I just reinstalled photoshop cc2014....and voila the problem disappeared again.....but I am 100% sure that, randomly, in the next days it will appear again.... so my provisional solution for now is just reinstalling the software.....and pray ...I guess.
I read that the adobe guys say that "yosemite and adobe cc stuff are compatible and no problems" well I think that, for them, the fact that the software just run on yosemite is reason enough to say is "ok" but those little "details" and little "lags" make the whole experience of working just....PAIN.....
my machine is a 15 inch retina with 16 gb of ram so WHY THIS IS THIS HAPPENING!!!!!!
thank you