Make sure you change the General Preferences Render Tab Settings to help optimize Render Speeds... that is where the number of threads and Separate Process options are.

You may want to play around with Bucket Size.. I find smaller is sometimes better overall speed. Scenes will have impact.. No Dynamic(Strand)Hair, you can stay with larger Bucket Sizes. I get better results with smaller buckets when using Strand Hair... Before you use IL, you may want to optimize your Render Settings. I noticed that what worked with IL off, worked with IL on, but it is faster with it off when setting things up.

ratscloset
aka John