We are looking for a powerful workstation system for Blender rendering applications. It’s crucial that the system can simulate scenes smoothly while remaining quiet. To achieve this, we’re considering water cooling, with radiators, a pump, enough fans, and water blocks for both the CPU and GPU.
If it was only 1 4090, then just a general AIO for the CPU and a normal air cooler on the GPU. Way simpler, cheaper, much lower maintenance and general noise and performance would be little different.
Of course fitting two 4090’s in a ‘normal’ case and motherboard isn’t easy.
Other then that, you only specifically state the need for simulation. I’d first make very sure that any workloads, both simulation and anything else you are really looking at doing, can make good/full use of two 4090’s and/or many multi-cores vs a few faster single cores.