QUOTE(Gentleman_League @ Aug 26 2021, 12:16 PM)
ahhh YES, VirtualBox will pop out whenever i tried to shut down my PC. Possible that's the one that eating up the RAM space, if i switch it off would it effect my android emulator?

Yes, Android emulator run on VirtualBox, it is a virtual machine that running your Android system la.
If you only running like 1-3 hours of Android emulator, but your RAM keep 90%, the only thing you can do is.
1. Just keep reopen your Android emulator, ensure VirtualBox also shut down in the process.
2. Turn off Fast Startup to prevent the memory leak bring over to next boot of your system.(hibernate is not reboot/fake shut down)
https://www.asus.com/support/FAQ/1045548/Or, you just add more RAM to counter it la.
Memory leak by virtual machine is old issues that hardly can fix, so, yup.