But I assume for way more energy costs? And the manual labour to sort out the different mainboards and make everything interoperable is not free either. But I guess it means lots of opportunity for unconventional low costs projects to scramble things together. Win 10 got another year of support, but I assume next year, even more computers will be avaiable quite cheap or for free.
It’s like when people replace their fridge with a “more efficient” one and wipe out any energy savings with the cost of the new fridge. The difference in energy use will not pay for the new fridge for many years and by then you’ve already replaced the new fridge with another newer “better” one.
you have to go for TCO to justify upgrades. energy alone most of the time doesn't justify replacing old hardware.
factor in space (=rent), age related increase in failure rate (=servicing), computer power needs (=opportunity costs) then together with the energy needs you find good points in time to justify an upgrade.
energy is the least relevant of those.
I suspect that if there was any reasonable amount of economic advantage to using old hardware we would see multiple organizations systematically building large datacenters out of the free hardware.
As a hobbyist, I would love to get my hands on more stuff like this. But I don’t see how it could be used for anything at scale.