Yes I just checked that the 2080 Ti has the same memory as a 1080 Ti, its just faster.
I also noticed that when I am using ray tracing both GPU’s (SLI) are under load. ( I don’t know why)
Though I am told have read its not supported. If it was I would have 22gb of memory on those cards…
Anyhow I’m still sat with my problem with an overloaded scene. I am reluctantly reducing texture sizes now.
I think I need to arm a veteran with a stick, and pay him to come and beat me up over my work in Unreal…
Thanks for the heads up on the memory limitations. Seems I have no choice but to reduce texture quality.
Thanks
Edit:: Attached an image, look at all that memory I am not using… 
GEFORCE RTX 3090 = 24GB Memory (Not out yet)
NVIDIA Quadro RTX 8000 = 48GB Memory (£6000+)
^^ 6000 are they out of their minds. … Back to reducing textures.