when I would check my task killer (ATK, which I hardly used), LOTS of things were open that I hadn't opened. The Verizon dude insisted on removing the ATK, and said that was causing the huge battery drain. I must admit, my battery life is back to normal today, and I have used it moderately. I don't know if it will be a fix for all the lag, but it is better today.
The Verizon guy you talked to was right. This is exactly the problem with task killers: they scare you into thinking a lot of stuff is running, but really, they're not.
Those "running" applications aren't running at all...at least, most of them aren't. Android puts things into memory that you use often, or it thinks you might use often even if you don't. When an app is in memory, it's not running--it's just a "save state" that will allow the app to launch faster and return you to where you you left off last. Think of it like saving a video game; when you load it, it gets you to where you were without having to do everything over again.
This doesn't use any of your processor at all--in fact, it cuts down on processor use for the next time you launch the app; it's essentially trying to load a game, instead of making you start from the beginning. If you had to start over, you'd be wasting time retracing your steps. By killing these apps, you're basically starting over when you need to use them again. This leads to using the processor more which slows down the phone, and uses up the battery.
By saving the app's state to memory, it's also not using any additional battery power: "free" and "used" memory use exactly the same amount of the battery, so there's really no benefit to having those apps not load into memory.
Additionally, you're triggering the processor every time you ask the task killer to do something, so you're using the processor and the battery when you open the task killer and ask it to kill something. Worse, if you're got it set to kill anything automatically, it's constantly making use of both the processor and the battery, leaving you with less processing power and battery for other apps--it would certainly show itself as lag.
Of course, it's in the app developers best interest not to tell you this. If they can scare you into thinking these apps in memory are running when they're not, and that they're using up your battery when they're not, they get more downloads, and perhaps more cash from paid versions or ads.
You've been tricked into using their app for something harmful. You should only use a task killer when you've installed another app that makes your system unstable--you kill the offending app so that the phone will work well enough for you to uninstall the bad app. Any other claimed value to task killers is false.
Keep in mind that these apps have been so problematic that Google has gutted their functionality in Android 2.2. I think that's a pretty high statement as to their value.
If you'd like information directly from an Android developer, try this link:
Android Developers Blog: Multitasking the Android Way
Here's a quote from that developer which may help you understand why those apps aren't really running:
"A common misunderstanding about Android multitasking is the difference between a process and an application. In Android these are not tightly coupled entities: applications may seem present to the user without an actual process currently running the app; multiple applications may share processes, or one application may make use of multiple processes depending on its needs; the process(es) of an application may be kept around by Android even when that application is not actively doing something.
The fact that you can see an application's process "running" does not mean the application is running or doing anything."
