abhibnl, Jan 31, 2019 : PubG is not optimized for S820. This chip is not used by any recent device. S660 is similar to S820, uses almost same Kryo architecture but PubG can run 60fps on this chipset. Reason? The developers have optimized the game for this chipset still being released on new devices. See, it's simple. The developers will invest time in something they will get profit from. S820/821 is obsolete now. No one will develop or optimize specifically for it. Accept the reality and buy a latest device. if you are claiming that it's running fine on custom ROM, then use a custom ROM and don't create threads here. We will what optimizations Pie brings along once its released but don't expect double frame rate with a software update. The developers need to optimize game code/graphics for the S820/821 platform.