My client is looking to build a rendering rig for Blender Cycles. We are debating on the new Nvidia RTX 2080 GPUs. Is there a max number of GPUs that Blender can handle on a single machine? I know some mining motherboards support 16 cards. Are there any bandwidth concerns using 1x slots and risers in Blender? At what point will adding more GPUs not be worth it in terms of building a separate machine?
Animations I can see better with multiple rigs (4x cards). But big poster size renders would need more GPUs per machine. For example, a 9:16 ratio, 80inch tall poster render took 18hours on a single 1080Ti.
Is there a “standard” amount of GPUs recommended per machine?