Cutting desktop power usage

You Can Use Jupiter

Jupiter is an applet which allows you to switch between maximum and high performance and power saving mode, change the resolution and orientation, enable or disable the bluetooth, touchpad, WiFi and so on.

You can install by adding the ppa ppa:webupd8team/jupiter and installing jupiter from the software center.

I'm not sure what the exact sequence of events was, but I just noticed that granola is running now. I know I tried installing cpufreqd and powernowd, but either caused Granola to be uninstalled. It may just be that the PC needed to restart.

It would be nice if the app showed more details about how often the CPU is being throttled and to what speed. I can see current speed with

cat /proc/cpuinfo

and to time at each speed with

cat /sys/devices/system/cpu/cpu0/cpufreq/stats/time_in_state

I'm assuming both cores run at the same speed. That shows speeds from 1-2.4GHz with most time spent at the lower speeds. I have a whole-house power meter. I'll see if that can tell me the difference the speed makes.

Update: I was too quick to celebrate. Today it's not working. I looked in /var/log/messages and found this for yesterday

Feb  4 07:50:20 zaphod kernel: [    0.560856] powernow-k8: Found 1 AMD Athlon(tm) 64 X2 Dual Core Processor 4600+ (2 cpu cores) (version 2.20.00)
Feb  4 07:50:20 zaphod kernel: [    0.560910] powernow-k8:    0 : fid 0x10 (2400 MHz), vid 0xc
Feb  4 07:50:20 zaphod kernel: [    0.560912] powernow-k8:    1 : fid 0xe (2200 MHz), vid 0xe
Feb  4 07:50:20 zaphod kernel: [    0.560914] powernow-k8:    2 : fid 0xc (2000 MHz), vid 0x10
Feb  4 07:50:20 zaphod kernel: [    0.560917] powernow-k8:    3 : fid 0xa (1800 MHz), vid 0x10
Feb  4 07:50:20 zaphod kernel: [    0.560919] powernow-k8:    4 : fid 0x2 (1000 MHz), vid 0x12

For today there is just the first of those lines. That suggests something went wrong, but where do I see the errors? Restarted and it was ok.