Laptop´s CPU runs on a lower clock

[carlos.alberto.montalvo.tagle]

http://prntscr.com/hysdt9
Laptop: HP Pavilion 15 p004la
CPU: AMD A10 5745m APU
My cpu runs on a lower clock that it should, as you can see on the image, the 4 cores are working on unstable and different clocks, sometimes (like 1% of the times) it boots up with the correct clock speeds, but as soon as i dissconect it, the problems return.
the laptop itself has a lot of problems, some of them are overheating, if a battery is connected, it doesnt recognize de AC, when i turn it off, i have to disconect it from ac, and reconnect to make the power button work.
It isnt the drivers or the os, because i have already tried to make a clean install of both win 10 and 8, i stayed with 8 because it looks that the performance is better than 10´s, idk if it is because its less resource demanding.
this laptop was actually given to me free, but is much better than the one i had before (a 1.30ghz dual core amd e300 apu laptop) so i decided to keep it for personal use.
What the problem could be? Could it be from the motherboard? if its so, do i have to replace it?
Thanks
Edit: I had the max performance power option already activated and it actually doesnt have a battery because it didnt worked when it was given to me, i found out about the AC problem because i tested it with a fully working battery from an another friend's HP Pavillion 15 laptop.

 

[LORDPrometheus]

It sounds like you have more than one issue here. First of all i would look at your battery settings and make sure you are not on the "energy saver" power plan. After that it sounds like the battery is broken but The behavior is very strange even if this is the case

 

[carlos.alberto.montalvo.tagle]

hello, i might just found the problem, i started to investigate on the internet and to check my AC adapter, and it looks like the original one is 90w and 4.62A and this one is exactly the half (45w 2.31A) Could this be the cause of my problems?

 

[jr9]

Well if the laptop doesn't actually have a battery installed and you are running on AC power alone, that AC adapter better be able to provide enough amps and wattage because the laptop doesn't have another power source to fall back on. I'd start by getting an adapter that has the right specs and go from there.