Why I asked this is: I had the same problem on my H69Pro+ and I did some heavely searching on the www on the processor capabilities.
As I read almost everywhere is that the amlogic S912 (the processor used in this device) is performing way down what you would expect, and even if it runs on (what is said) 8 core it sucks bad.
I discovered on my own device that the processor temperature also is way too high and runs up to 87 degrees celcius where 50 is actually what you would like to reach on max performance.
Although the amlogic S905, which I also own, runs up to 78 degrees and is actually to hot too does the job way better on just 4 cores.
I had the bad luck to frie the S912 due to
I guess high temp and had to send it back to the seller under warranty and have decided to abandon the S912 untill better processors come along.
I hope you can get this problem solved but bear in mind that the S912 is not happy when you run Kodi on it.
Aas far as I could detect before the damned thing fried was that there was no problem whatsoever when I played my movies with the build in mediaplayer on the device.
Just my 2 cents