You can do a LOT to minimize power consumption, some of which you listed above. Some choices can make a huge difference in total cost of power: undervolt the GPU, underclock the GPU RAM, use 90Plus Gold or Platinum PSU @ 240V, host them in an area with cheap electric rates, supplement with solar, ect. OTOH, some features will lower power usage, but aren't really worth it: disable devices in BIOS, undervolting CPU/MB, buying a low power CPU, booting from flash drive rather than HD, etc.
Spending all kinds of time and money just to cut 10W here or there will literally save you less than a $1 per month. Undervolting the GPU and saving $15 per month? Worth it. Undervolting the CPU/NB/MB/RAM to save $0.50? Not so much.
And this is not even getting into the discussion about how the difficulty is about to explode, and GPU mining will be unprofitable in a matter of weeks. That's a discussion for a whole other thread!
Spending all kinds of time and money just to cut 10W here or there will literally save you less than a $1 per month. Undervolting the GPU and saving $15 per month? Worth it. Undervolting the CPU/NB/MB/RAM to save $0.50? Not so much.
Using DC directly (from batteries--no inverters), you could ditch the inefficiencies of PSUs--and even the PSU all together. This would shave off cost of PSU, waste less energy and be one less thing to break down.
You obviously know nothing about building and powering a PC if you honestly think this will work. Like seriously WTF?!And this is not even getting into the discussion about how the difficulty is about to explode, and GPU mining will be unprofitable in a matter of weeks. That's a discussion for a whole other thread!