This issue should be affecting all stock ROM users of TAB Pro 8.4.
I noticed it a while ago and recently had some free time. The issue was narrowed down to Samsung's buggy mpdecision binary in /system/bin and you need root access to fix it. There are two ways to do it (you'll need terminal and file manager with root access rights):
1. Open terminal, type "su" and then "stop mpdecision". Open Root Explorer, navigate to /system/bin and rename "mpdecision" file to something like "00mpdecision". Reboot. All cores will be running at 300 mhz when idle and tablet will feel noticeably smoother and faster. I did not see any serious impact on battery while running this way for 2 weeks already.
2. Download attached mpdecision file from CM11 modrianwifi ROM, unrar it and transfer it to your tablet. Open terminal, type "su" and then "stop mpdecision". Open Root Explorer, navigate to /system/bin and rename "mpdecision" file to something like "00mpdecision". Copy new mpdecision file into /system/bin, change ownership to root:root and access rights to rwxr-xr-x.
Reboot. The issue will be resolved for good and unused cores will be shutdown properly. Tablet will feel the same way it was before file replacement.
Hope it helped.
Originally Posted by favero_
I noticed that in my Tab Pro 8.4 right after turning it on, when I'm not doing anything and just staring at the monitor it let only one core on clocked at 300MHz (using dashclock CPU information extension). So far so good.
The problem is that after some time, in the same context (doing nothing staring at the homescreen) it let two or four cores on clocked at 1497, so I have to reboot in order to save battery.
Any ideas why this is happenening? Does that happen to you?
P.S.: Battery saving settings turned on