Compared to which Sony processors? When one generalizes it often the case that no supporting data realy exist and that one is merely speculating. Post your side by side sensor data of the processors you state efficiencies for. CIPA is not an international engineering standard.
We are all speculating but making some considered guesses based on assumptions.
CIPA has been going for ~70 years and virtually all camera manufacturers are regular or supporting members. They have a variety of standards that they collaborate on. It is the only measure that the manufacturers publish their specs against.
Happy for you to tell me what engineering standard is relevant for photographers if you don't like CIPA. At the end of the day, togs just want to know how long a battery will last for their shooting style.
From a very rough perspective, Sony's FZ100 battery is approximately the same capacity (+7%) as the E6NH but the difference in CIPA ratings and the thermal limitations across a number of bodies would indicate that Sony's processors are more efficient than Canon. Clearly CIPA is an average but ~30% between R5/A1 (EVF) in not insignificant. Different shooting methodologies mean that CIPA is indicative but still a measure. There are lots of other factors eg EVF refresh rates, what temperature Sony/Canon will allow internal semiconductors to work up to, etc.
From a logical perspective, the Canon's choice of 45mp for the R5 means that no oversampling is needed using the Digic X. The A1's dual Bionz XR needs to oversample from 8.6k and process via codec to 4:2:0 XAVC HS vs virtually no processing for Canon raw. The use of the CFe Type B card seems to also generate a lot more heat whereas the A1 can record to the SD card as the bit rate isn't as high. The A1 is smaller than the R5 but the use of dual processors could either mean better heat distribution.
My assumption is that Sony's engineering history for video processing for their PS consoles would be portable technology. The camera processors could also have access to narrower lithography processes based on Sony's overall semiconductor volume. I haven't seen any teardown of the A1 yet. Will be interesting to see what is on the inside
