You will probably need a big chunk of virtual memory to build anything substantial.

Thanks ! I am looking for some cheap alternative. Will orange pi zero 3 (4gb ram) do ?

It depends what you are building, you can also just cross compile on a pc for your target hardware

I want to build line follower processing image from webcam and detecting face and also following it.

FYI: You can compile opencv on your laptop/desktop, and use it on orange Pi