Daz does a very poor job of reporting the amount of VRAM memory consumed by the program when rendering. If you view the log file obtained under the troubleshooting menu in Daz, you generally find that actual VRAM consumption is roughly double what is reported in the log file. If it drops to CPU rendering, your only option is to adjust the rendered content or tweak the rendering settings. There are many tips on how to do this earlier in the tread, including some from myself.But 64 MiB is only 67MB. How can a 8GB Card not find that small amount of memory?
As a bit of a guide, with 8GB VRAM you can render 2 x G8 figures with clothes and some background, without doing anything to reduce the object mesh density or playing around with reducing sizes of textures.