[1] O. Mutlu, S. Ghose, J. Gomez-Luna, R. Ausavarungnirun, A Modern Primer on Processing in Memory. https://arxiv.org/abs/2012.03112
32 bit multiplication : 3 pJ [1]
The energy savings come from not transporting data.
[1] http://www.sigmod2014.org/damon/slides/picojoule.kozyrakis.p...
https://ieeexplore.ieee.org/document/9073325
Edit:
A more accessible (in both senses) survey paper on Near-Memory Computing:
(obligatory scihub reference)
Tip: if you contact the author(s) of a paper that is of interest to you and ask for a version of it, there's a good chance that they'll gladly accommodate. I think generally authors don't even have any financial benefit if you pay for the paper (it all goes to the publisher).