It varies case to case. For example, a person who did not travelled to other countries during last ten years (based on refugee forms) may take less time in comparison to those who travelled and spent time in multiple countries as information need to be collected from multiple countries. Also, I believe background check processing time depends on family size too as checks need to be made on all family members. Furthermore, some countries are slow respondent to inquiries made on Refugee than others.
These are some of the factors that (in my view) affect background check processing time.