alt Hacker News> the problem is that work/watt is dropping for newer hardware, so there's a point where even if you had an equivalent quantity of 10-year-old GPUs, powering them for some period costs $40k
Sell the old-gen GPU's to on-prem users (including home consumers) who are going to run them a small % of the time (so power use is more or less negligible to them compared to acquisition cost), problem solved.
The same math applies for on-prem/home users. If you actually have some workload where it makes sense to get a free GPU that costs $40/hour to power because you only need it for a few hours a month, it's probably cheaper to rent a more efficient GPU from someone who can power it at a lower cost.