after some time, I finally decided to do something about energy saving. I bought one of these to keep my home server running on constant power outages we got here. I installed apcupsd daemon and the CGI to provide informations about the state of battery, etc. I noticed that my home server - amd64 dual core 3800+, 3 SATA disks -, with a 19'' TFT monitor, DSL modem and a WRT54GS use 15% of APC capacity when idle and when I was compressing a big file with bzip2 (thus using one core, plus two disks (RAID1)) the usage jumped to 20%! It's 60VA more. Amazing.