Why is dataaccess using so much cpu usage?

[iMore Question]

My iphone get extremely hot while charging, and charg really slowly. While plugged in and unplugged, dataaccess is using 90+% of cpu. I have it on ios 8.4 jailbreak. Installed MTerminal in cydia, and top. Havent installed any tweaks or things like that so it,s a fersh jailbreak.

 

[Bigeric23]

Maybe because it's jailbroken and not optimized as Apple intended?