Wayne Stallwood wrote:
Tell me about it, I feel guilty about leaving this AMD 64 monster running 24/7, but I need to access it remotely (as do others). I wish it could clock itself down to say 300MHz when it is idle (and perhaps then shut down or idle the CPU and PSU fans) but at least under Linux there seems to be no way of achieving that.
Check out speedfreq. It will let you set the policy by hand, or adjust it dynamically, and let you monitor it. For example, this is what happens when I stop reading email and kick off a compile:
mak@yoda$ speedfreq -m New policy: dynamic 1000-2200 MHz CPU new speed 1000 MHz, 96.0784% idle ... CPU new speed 1800 MHz, 87.7551% idle CPU new speed 1800 MHz, 0% idle CPU new speed 1800 MHz, 0% idle CPU new speed 1800 MHz, 0% idle CPU new speed 2000 MHz, 0% idle CPU new speed 2000 MHz, 0% idle
I always use the dynamic policy, and as a result, in its usual idle state my AMD64 3500+ (in an ASUS A8V Deluxe) uses less power and generates less heat than the P4 it replaced. And provides more performance when I need it, and can run 64-bit should I so desire, but without forcing me to. Lovely.
If you look at the "AMD Athlon™ 64 Processor Power and Thermal Data Sheet" on amd.com you'll see it lists P-states, supported frequencies with documented "Thermal Design Power" usage, per model. For example, at maximum p-state my cpu lists 89W, at the min p-state 22W; that's quite a difference. When I chose my cpu it was based on the supported p-states.
I guess it's market forces, people buy computers based on bogus performance figures and hardly anyone seems to consider running and environmental costs.
This is changing, driven by the common desire for quiet computers. If you're into that, check out the forum on www.silentpcreview.com.
Also, if you want to experiment with the energy costs of your various bits of hardware, you're welcome to borrow my power meter; it can be quite illuminating (CRTs really are power monsters), and gives you a different perspective.
-- Martijn