There is definitely an under-served target memory size of 48GB - almost everything aims for: 12, 16, 24, 32, 64, ...) But most dual-gpu setups, 3090/4090 (and some mac configs afaik) have 48GB, and most 64GB systems would do well with the extra 16gb of overhead saved. 48GB is also moderately common in PC memory configurations since 24gb DIMMs are a thing.