forgot to add, check the figure SubD render level, reduce to 3 or 2 even in case it is 4 or even more, the memory requirement for levels above 4 are HUGE, and from that distance Subd 2 will look pretty much identical to 3 - useful if you want to fit more figures in your render at once
there is a helpful addon to check these things - "Iray Memory Assistant", Daz doesn't have anything like that built in, and actually in one of the recent updates they took out log file messages relating to memory consumption for some reason - it was very useful to see quite early when something is wrong with the scene and that it may not fit into GPU memory (which will make it fall back to snail pace cpu rendering)