LPDDR4x has various power levels based on whether it's actually being used or just keeping data from corrupting. The latter is much less memory intensive and runs at much lower voltages. You may have a point about SSD depending on how much read/write is happening.
Check out this comparison of the passively-cooled M1 Macbook Air vs both Intel and AMD Surface 4 machines.
TL;DR -- AMD loses 25-50% of their performance as soon as the plug is removed. Their actual power usage spikes at 40w (for a 10-25w U-series CPU). No matter how you cut it, Peak M1 power usage is about half for similar performance.
Insult to injury, the M1 not only has far better performance, but it's also cheaper.
But I think it’s maybe twice (three times tops?) as good as the competition on a power/perf basis, not the 10x some people keep claiming when they compare the 10W claimed by Apple against the 100+W TDP of similarly performing AMD/Intel CPUs.
Incidentally, assuming the benchmark they’re running is Geekbench (seems likely at this point), I’ve just run a pass of both CPU & Compute GeekBench5 benchmarks with iotop running in the background & neither did any disk IO of any significance during the run. I think the peak throughput I saw was 150kb/s and that might have been something else on the desktop (I didn’t bother killing anything). Most of the time there was no IO at all.
So, if it was GeekBench they were running (seems plausible) then I think we can assume that the SSD is idle & that the Compute benchmark is really a GPU benchmark.
Check out this comparison of the passively-cooled M1 Macbook Air vs both Intel and AMD Surface 4 machines.
https://youtu.be/7yTWGjYFiC0?t=509
TL;DR -- AMD loses 25-50% of their performance as soon as the plug is removed. Their actual power usage spikes at 40w (for a 10-25w U-series CPU). No matter how you cut it, Peak M1 power usage is about half for similar performance.
Insult to injury, the M1 not only has far better performance, but it's also cheaper.