You have probably heard reports that the OnePlus 3 is having a difficult time with RAM management. This surfaced when Ash from C4Etech uploaded a speed test pitting the Galaxy S7 against the OnePlus 3 in a Speed Test. The speed test consists of opening 20 or so apps, closing and then reopening the apps. A phone with "Good" Ram Management should be able to keep apps open in the background for quick access later.
While the OnePlus 3 has plenty of memory, a whopping and unnecessary 6GB, it still was not able to keep even as many apps open in the background as the Galaxy s7 which only has 4GB of RAM. As it turns out this is not a bug, and won't be "fixed" by OnePlus. The phone has an Aggressive RAM management policy by design. This was done to save battery life, and it seems to actually serve its purpose as many users are reporting upwards of 6+ hours of Screen On Time with the 3,000mah battery.
If speed and multitasking is more important to you than battery life there is a line of code that can be changed in the Build.prop which allows the OnePlus 3 to keep more apps open in the background. If you make this mod your multitasking capabilities will likely improve, but the trade off could be more trips to the power outlet for charging. Luckily the Dash-Charge will get you recharged in a Jiff!
via XDA