A good recommended Android emulator right now, Nox and MEmu.
Both are highly customisable in the settings. RAM allocation, Core allocation, and even Device phone emulation.
But i recommend MEmu because they support both Android 4 and 5.1.1 while nox only still only at 4.
CODE
http://www.memuplay.com/
https://www.bignox.com/
Dual BootingIf you wanna use PhoenixOS, i suggest go for their 1.2.3 version rather than their latest 2.0.7 based on Noughat. Its still buggy.
And bye RemixOS, hasnt been maintained since November 2016.
If you dont trust these china emu, download yourself Android Studio from google (over 7GB) and you can do the hard setting lmao.
Anyway i have been using Nox since forever. Nothing shady with them.
If you're scared of malware apps pre installed, both emu has root management. If you know how to, you can easily debloat it

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EDIT : ok i know dy how to check. seems like my memu using android 4.4.4. how to upgrade to android 5.1.1?