I found out that the Intel Atom N455 in my netbook can run the x64 instruction set. I don't have any compatibility problems with old x86 softwares and drivers, but I need to save battery power.
I understand that using long mode would make the instructions bigger, and this would probably increase the power consumption. However, long mode will also take benefit of the larger and additional registers, accessing the RAM and the cache less frequently, decreasing power consumption, right?
So, what's more power efficient to use on a computer like this, a x86 operating system or a x64 operating system?