My computer did not have enough RAM, but i did not want to buy "expensive" DDR2, so i bought a new board for DDR3 :-))
I found no useful numbers about the power usage of a system without GFX card and furthermore probably more people are interested in the effect of a "80 Plus Gold" PSU.
For comparison i measured with an older PSU, that most likely was claimed to be efficient 5 years ago.
The following components were connected:
Intel DZ68DB (default config, only UEFI was activated)
Intel i5-2500K with intel stock cooler
8GB RAM
2TB HD (WD20EARS) (uses about 4W)
120mm fan @600rpm
DVD drive
1 monitor connected (when 2 screens are connected the power usage goes up by 4W)
Software: Ubuntu 11.04 everything default, no power saving tricks
5 years old PSU: Sharkoon SHA480-9A
standby 2W
gnome desktop idle 35.5W
mprime 1 thread 65.5W
mprime 2 threads 82.0W
mprime 3 threads 96.9W
mprime 4 threads 111.0W
new PSU: Fortron Aurum 400W
standby 0.5W
gnome desktop idle 27.3W
mprime 1 thread 52.6W
mprime 2 threads 67.7W
mprime 3 threads 82.1W
mprime 4 threads 95.0W
The SHA480-9A PSU was used with a AMD Athlon64 with 2*2Ghz and a passive ATI X600 GFX before and the IDLE power usage was 74.5W.
Power measurements were done at the 230V outlet.
