Please look at these number with the following grain of salt, when optimizing programs. They are trumped by cache usage patterns [1]:

    Loading (fig IV)
    
    Location    Energy (pJ = pico Joules)
    L1          64   pJ/Byte
    L2          121  pJ/Byte
    L3          254  pJ/Byte
    RAM         1250 pJ/Byte
    
    Adding integers with SIMD (fig VI)
    428 pJ/op, for 8 Byte/op; this means: 
    53 pJ/byte

So it takes actually 20 times to fetch data from RAM than to add it to something! And most often this is also the source of latency. Generally energy is linear to the distance signal has to travel, and that's the same for latency.

That's why successful data structures are sized a tiny bit under L1/L2 sizes! (BTree chunks, ring buffers).

If you've been following hardware, it's all about putting RAM closer to compute at the moment with chiplets at the moment.

[1] https://tu-dresden.de/zih/forschung/ressourcen/dateien/abges...