[ravel-bar-foo]

I was going to disagree with you, but a back of the envelope calculation shows that the energy of computer production is probably equivalent to that of a few hundred hours of use, and so if you can save 10% on energy you are probably environmentally justified in switching to a new device. This is very counterintuitive to me.

To first order the upper bound for carbon cost of production/recycling is going to be a multiple of the energy required to melt the components. Call that multiple four: production of raw materials + reshaping in factory + recycling of materials at EOL + energy cost for assembly. So a rough upper limit of the energy to switch a computers would be four times the energy to heat the computer's mass in water (4 J/gC) up to the melting point of silica (1900 C), and a rough lower bound would be the same using the heat capcity and melting point of iron (10x lower heat capacity, 1500 C), and neglecting assembly. For 1 kg of material, that gives a range of 1.8 and 32 MJ. Now you can compare to the energy used. For myself, I'm on a 2 kg laptop that draws up to 250W, but conservatively 50W. That adds up to 32 MJ/kg in 400 h. If I can reduce the energy use by 5W with a new model, that will pay itself back in 2 years of workday computation. Crazy.

Caveat: there will be additional non-CO2 environmental costs. Most components are not recycled, and resource extraction is also environmentally damaging.

[pdimitar]

The only remark I'd have here is that the cost to produce is amortized over the course of producing several hundred or even thousands of units. It's still there but is greatly reduced per unit I think.