i have a problem in unreal engine that it is slow and my ram is 4 GB. is there any way to make engine fast?
thanks in advance
You could change your quality settings -> under the quick settings tab. Also make sure that you use the right gpu (laptops sometimes have two) and that you run your PC with the “high performance” power settings 
Also you could try to increase the virtual memory of your system. Even that wont be enough at some point though, so i would get at least 4GB more RAM if you can.
RAM won’t improve speed as much though over getting a better CPU or a better GPU, one of the computers I was working with until recently had 4GB but it was fine because the processor and GPU were good.