This matter doesn't really affect the phone's usability in any way, but I've noticed after upgrading to iOS 4, the fluent 60FPS action has changed to spike around 25-30FPS to 60FPS.

These spikes occur every 2-3 seconds and can be seen when swiping across pages for example. The page swiping in iPhone OS 3 had a solid 60FPS feel to it, but that is nowhere to be seen in iOS 4.

Or am I just imagining all this? I'm using a jailbroken iPhone 3GS with a firmware of version 4.0.1.