My system is 3090 Ti (24gb VRAM), 32gb DDR4, i7 8700k, Windows 10.
I've upgraded GPU recently because 8gb of VRAM on my old one wasn't enough, causing out of memory use or crashes in heavy scenes. However the new GPU acts similarly in heavy scenes, it crashes at around 14-15gb use of VRAM. It never uses all 24gb of VRAM.
The theory I've read online is that I need to have twice as much RAM as I have VRAM because of some Windows hard lock. So I need 48gb of RAM apparently? Could this be true and is there a way to unlock VRAM without upgrading? Task Manager shows I have 24gb of dedicated GPU memory, 16gb of shared GPU memory and 40gb of total memory. Why can't Blender use more than 16?
I render in Cycles: OptiX. My previous GPU 2070S 8gb was able to fully utilize all it's VRAM with scenes going up to 8200mb in VRAM use.