While it may be the app, I have gotten slow-downs before it was installed. I either reboot or kill running apps from the recently used apps list. Usually speeds it up.
I should note my iPhone 4S does the same thing: gets slow at times.
That said, I mostly use GGC in games and have not noticed any lag in them that I could notice. I would think a game would show it the most.
My biggest issue with many games is screen tap recognition delay. Noticed it from day-one, long before I rooted. It is making many games unplayable. I know it is not the hardware in the N4 because of how fast tapping the nav buttons, among other things is. I hope this is not "just the way it is on Android." A perfect example is jetpack joy ride: the delay makes it very difficult to play the game compared to my iPhone/iPad. Heck I even dusted off my very first iPhone 1st gen and it played the game without that screen tap lag (albeit the game itself struggled to keep up). Yet the reviews on google play are positive? wtf
EDIT: WOW! I just figured out where the screen tap delay was coming from: having magnification on in accessibility under settings. That feature lets you tap 3 times quickly to zoom the screen. Apparently that adds a small tap delay in order to process the 3 taps. Turning that feature off made the game I mentioned above not have any screen tap delay at all.
Michael
Yeah I shouldn't blame the app so quickly. It's been running very smoothly all day today. I really really love this program. The only thing I miss is the status bar, I wish it had an option to turn off the navi bar but keep the status bar on.