Could the iPhone lag be faulty hardware related?

[HarryPot]

Since long ago I had the lag in animations in my iPhone 4.

A couple of days ago, the wake button stopped functioning. So before taking it to Apple I made a restore and started with a clean install. The laggy animations continued in my iPhone. So it wasn't the fault of many apps running at the same time.

Today they replaced the iPhone for a new one, and this one, even with all my music, apps and info loaded, is completely lag free.

My former iPhone 4 was one of the first batches I suppose. So I was wondering if the lag in animation could be the cause of faulty hardware.

 

[the.sheepdog]

In your case could be. In others? No way to tell. My iP4 has always been sleek and smooth. I didn't set mine up as new either but a follow on to my 3GS so it could have some redundancy. But mine is fine.

 

[rjohnstone]

It's entirely possible your old phone had some sub-par ram that slipped passed the QC testing.
Based on what you said, I would say that you had a defective phone.
It happens.