Just to add to this, I ran into this issue (my current workstation is a laptop with max memory of 32gb). I needed to keep the render elements I was using but was exceeding my ram limit so I found that by downsizing any texture over 4k by half this drastically reduced the memory consumption from 98% to 30% and I was able to finish the job. I do recommend more ram atleast 64 to keep artistic freedom and visual appearance, but sometimes things must be done to utilise your setup I suppose. A good script I found to do this automatically (resizes 1k,2k or 4k, copies the bitmaps to a new folder and relinks them for you including bump,spec,gloss maps etc) is found here
https://renderpeople.com/plugin/Be aware this will not work for CoronaBitmap - only standard bitmaps
