When are all 4 cores needed?

[Nick33]

Ok so, i have the app Battery Doctor on my s4. It's got some cool features, but the verdict is still out on whether it actually saves me battery life.
Anyway, there was a feature added to throttle down cpu speeds when the phone is idle. Its not that intricate, it's on or off.
So i had the app running and ur able to see all 4 cores. I noticed that only the first core was doing something. For example : it stayed running around 380mhz and jump to 1600 when i touched the screen or something simple.
But i noticed that the other 3 cores remained "sleeping. " so i started running a few other apps, even started up a game with the other apps running in the background, went back to battery doc, and STILL only one core active. The second core jumped for a second or two, but that was it...
What i DID see is my active app widget turn red(bad).
So what the hell is up? When do the other cores wake up and do something??
Sure, maybe it was a misreading from the battery doc app but like i said, i did see the phone start to get bogged down.

Is this normal? Bc it's got me wondering if this may be the reason my phone gets unbelievably hot...

 

[Rxpert83]

I'm in the camp that most battery saving apps don't work, but that's not really the meat of your question.

The short story is you don't want all 4 cores running. They'll only pop on BRIEFLY during periods of high CPU stress and then go offline again as soon as possible. This is good.

I'm betting they likely went on when you opened the other apps, and were off again by the time you made it back to the monitoring app. Ideally you need an app that shows the history and not real time stats.

Speaking of... It could be a misreading by the battery saving app. There are a number of apps out there who monitor your system stats, and you may have better luck with one of those than an app that's primarily focused on saving battery but also has this monitor feature. I've always been a fan of apps that do a few things well, rather than the all in 1 apps that attempt to be a 1 stop shop.

Hopefully some of that helps