Root is the best way and the easiest way. It brings back even the worst and oldest devices to life in usage , especially for gaming.
My s3 mini wasn't super fast but it was fast enough.
My S6 is very fast but I run DQ at 1.5ghz and 1.0ghz extra 4 cores. Well actually 8 cores but 2 disabled. Da doesn't use many cores though but extra cores do help.
I also play DQ at 720p instead of default 1440p or even 480p at times because I want the very best performance and low lags in graphics. My CPU is more than able to handle r and 1GB of ram is enough (if no other things running in background).
I have 3GB ram so i can multitask and DQ well.
I also undervolted the crap out of my phone to reduce power consumption by so much that I gain many extra hours of battery life. Not just that but stability.
Although I would never recommend Samsung for gaming due to their DVFS constantly thermally throttling even if your device isn't even heating and I had to disable it to play without constant stuttering, even on super fast device.
However my 1.5ghz is faster than some people's 1.5ghz and faster than PCs of 2005 1.5ghz . It's pretty darn fast actually! It's not even comparable to a PC gaming performance but it feels so speedy on android. Then again, My S6 has good IPC so low clock speed is actually good.
1ghz on my S6 is faster than the S3 mini 1ghz .
I even underclocked the graphics so that I run DQ with less power. DQ runs very well on some low end devices provided the right settings , though my S6 is fast even at very low speed.
In today's world, 1ghz would be too slow but not for phones. 1ghz in the S3 mini costed too much S3 mini battery but it was okay. My S6 at same speed however would be as fast as overclocked old phones