Just got Galaxy S4, it's laggier than iPhone 4s!

I've been using iPhone 4s for two years. After playing with a friend's One X+, I decided to switch to android and got an S4 octa-core soon after.

S4 started lagging the moment I turned it on the first time, general animations skipped frames and so did the gallery app. Instagram and other apps kept crashing too. The lag went to a whole new level when I filled the 32gb card with music. On my 4s, there was around 45gb of media and it never lagged or slowed.

It has been almost two weeks and I'm in love with android but all this lag gets annoying on this high-end device, I think I'll be returning the S4 and getting an iPhone5, even though I don't like the upcoming OS7 and iPhone5 is getting old.

I'd love to hear your thoughts on this lag problem.