A thread about mobile games and performance optimization

Warning. If you try similar stuff, better know what you're doing as you might fry your phone. 
Note. It's pretty technical so if you're not interested in technical stuff, better move on to another thread. I don't want to bore you. 

I still use a 2015 Nexus 6p as I like the design and dislike the current Pixel series. But the phone is aging as three years is, in the mobile device market, a long time. This phone uses the Qualcom Snapdragon 810 with a little.BIG configuration meaning, that the cpu has two clusters with slower and faster cores in a 4+4 configuration. 

While gaming I noticed slow downs and when monitoring the cpu clock, it always hovered around the 1,something gigahertz mark which is pretty slow, as the cpu is advertised as 2,0 or 2,1 ghz if I remember correctly. So, this got me thinking: How and why does the cpu act like it does and why is the gaming performance, especially with demanding games like BoT or PUBG not so good? 

From playing games on the PC I know, that still a lot of titles work great with having two fast cpu cores. So I thought that a possible solution to improve gaming performance of the phone, was to abandon the 4+4 cores and disable some of them. The cores in the little cluster are energy efficient but not so powerful. The cores in the big cluster are powerful but generate a lot of heat, so we don't want too many of them active. I then played around with different configurations. 4+1, 2+2, 3+1 and so on and it seems like having active 3 of the slower cores and one of the faster cores works great with games. But disabling some cores is just part of the optimization. What I also did was increase clock speed to the maximum which is still within the specification for the 810 Snapdragon. Small cores were set to 1,7 ghz maximum and big cores to 2,1 ghz. 

Now here's the thing. If on the big cluster only 1 out of 4 cores and on the small, more energy efficient cluster, only 3 out of 4 cores are active at any given time, the cpu in total has to dissipate a lot less heat and thus, can keep the frequency of the active cores all the way up. What did I get as a result? Battle of Titans wasn't playable at all at the default 4+4 configuration. The graphics just stuttered all over the place and I could not aim, as framerates dropped to less than ten fps per second. With 3+1 at high clock speeds, I can play BoT perfectly and the phone doesn't throttle anymore. 

On newer devices by disabling some cores, you might get better battery life and a cooler running device but you won't gain any performance, as the newer cpus are already very fast without optimization. But if you're running some older device, you'll be suprised how fast and cool your device can be. I really wonder why the manufacturers don't do this kind of optimization in the factory. 

I hope that this has been interesting and if you have technical questions about my write, feel free to drop them here in the thread. 

Addition: For these mods you need root access to your phone of course, and you'll also need a custom kernal which let's you fiddle with the internals of your phone.