That's just an artifact of Intel disabling ECC on consumer processors.

There's no reason for ECC to have significantly higher power consumption. It's just an additional memory chip per stick and a tiny bit of additional logic on CPU side to calculate ECC.

If power consumption is the target, ECC is not a problem. I know firsthand that even old Xeon D servers can hit 25W full system idle. On AMD side 4850G has 8 cores and can hit sub 25W full system idle as well.