[Q] Phone gets unreasonably slow when song changes topic

It bewilders me everytime it happens. I'll be just doing general things on the phone, listening to music in the background, RAM usually on the 800mb+ spectrum, and then when the song changes, at one point my phone was near frozen for almost 40 seconds, while nothing else is going on. I disabled most bloatware, and very obsessively monitor my RAM usage and currently running apps, but when a song changes, whether natively stored on my SD card, or Pandora, the phone gets crazy slow. The weird part to me is, for example, I'll be playing a PS1 game and have my framerate counter in the top, and it'll usually be at 60(Full speed), but when the song changes in the background that I'm listening to, the game will seem like it's running at like 5 fps for like 15 seconds, and yet my framerate counter still displays the normal 60, as if my phone isn't actually slowing down, but it really is. Any way to remedy this?

[Q] Which rom gets you the best battery life? topic

Okay, let's face it, this phone doesn't have a great battery life. The most i ever managed to get out of this 1500mAh battery was 22 hours, more or less.
That was on the glorious cm11 haha
Anyways i'm rolling over all the roms since December and now i can't find one that gets me over 14 hours, that actually is really bad. My use is mainly whatsapp so i don't think i'm giving an hard time to my battery. I tried looots of apps and roms. I feel stupid haha.
So my question is, what rom and which settings gave you the best battery life and how much did it last?