64GB uses marginally more idle power than 32GB.

Yes, but the difference is tiny – single-digit watts at most. You won’t notice it on your electric bill or feel it in your case temps.

On DDR4, idle power comes mostly from keeping the memory controller and the DRAM chips refreshed. More capacity means more chips, so there’s a small increase. But if you’re running two sticks either way (e.g., 2x16 vs 2x32), the extra power is maybe 2-3W. Four sticks vs two sticks? That difference is larger, but still under 10W idle.

Unless you’re running a server 24/7 on a tight power budget, this is not a reason to choose 32GB over 64GB. Get the capacity you need.

Don’t optimize for a watt you can’t feel.