This suggests that the early GDDR6X devices had high power consumption, i.e. the power consumed by a single chip is probably around 3 W instead of the 1 to 2 W that has been the norm for a while. It would be nice if we could get a screenshot from a 3090 Ti in the same benchmark. I also noticed that the combined chip and VRAM power drawn is barely 75% of the board draw. It seems that the VRMs are rather inefficient.
Honestly, given the high prices of the flagships, HBM is beginning to look better for them. An additional 500 to 600 dollars won't bother the buyers of these cards. Also, for laptop GPUs, LPDDR5 would be better than GDDR6 etc. Widen the interface by 2x and you would still save power.
Apparently it's a lot lower, the way 3090 Ti has been re-engineered improves the memory subsystem in many ways. The
3080 Ti does not have this improved memory, it uses a lower bin 19 Gbps G6X chip that is also used in the RTX 3070 Ti, so it's not a valid comparison. However, it is also a newer revision from the original 3080 10 GB's chips. Basically:
3080 (original 10 GB model) uses 10x 8Gbit Micron MT61K256M32JE-19:T (D8BGW), rated 19 Gbps
3070 Ti (8x), 3080 12 GB, 3080 Ti (12x) 8Gbit Micron MT61K256M32JE-19G:T (D8BWW), rated 19 Gbps
3090 uses 24x 8Gbit Micron MT61K256M32JE-21 (D8BGX), rated 21 Gbps
3090 Ti and 4090 use 12x 16Gbit Micron MT61K512M32KPA-21:U (D8BZC), rated 21 Gbps
As of now, other Ada cards use the same chips as 3090 Ti and 4090 but in lower quantities appropriate for their bus widths
Which makes the RTX 3090 unique in its extreme memory power consumption, as it has the first generation and first revision of chips, at their highest speed bin and you actually need to feed 24 of them. It's the worst case scenario.
From my understanding, the problem with HBM is that the silicon and the memory must be flawless and cannot be tested until packaged, if there's problems with the substrate, GPU ASIC or in any of the active HBM stacks, the entire package has to be discarded. This greatly reduces yield and was a cause for concern for AMD with Fiji and the two Vega generations. Titan V as well, it had a bad/disabled HBM stack (3072 out of 4096-bit enabled). It might not be feasible, especially considered the more affordable products tend to use harvested versions of the higher end chips, or they just disable them to maximize yield and profit as Nvidia has done with the 4090.