Common causes of lag?

[ClumsyNinja21]

In general, what are common causes of lag on the OG? Is it memory? Kernel? I need to make sure I rule out things as I work thru it. I want to learn why it happens instead of just simply changing rom, etc. I like to know why things happen.
I searched forums and found answers to specific incidents but am wondering if there is a commonality in causes.
Thanks!

 

[LifeIsABeach]

AntiVirus and TaskKillers are a big cause of lag. With Froyo the stock launcher seems to lag at times. LauncherPro or ADW launcher will fix that.

 

[ClumsyNinja21]

AntiVirus and TaskKillers are a big cause of lag. With Froyo the stock launcher seems to lag at times. LauncherPro or ADW launcher will fix that.

Thank you. I will write those down!