The only time the 6s substantially beat the s7 was when originally loading games. And considering that the resolution of the s7 is nearly 3x as high as that of the 6s, I don't really see a problem as you are pushing so much more pixels. It could also be that the games are not optimized for the s7, as there are so many hardware options on Android. This could be an app developer issue. They focus more on ios.
Once loaded the games stayed in memory,which is a major improvement over the s6.
If you want to see bad memory management, take a look at my turbo 2, which kicks apps out of memory badly. Price wise the turbo 2 starts at $624,and came out after the iPhone 6s.
http://forums.androidcentral.com/motorola-droid-turbo-2/604030-turbo-2-kicking-apps-out-memory.html