YES! Another website dedicated to reducing power on linux machines:
LessWatts.org"LessWatts.org is not about marketing, trying to sell you something or comparing one vendor to another. LessWatts.org is about how you can save real watts, however you use Linux* on your computer or computers. "
Being a linux user and power miser myself, I can honestly say this site does have a lot to offer. In my brief visit tonight I learned about "tickless" and IRQ balancing. Well done!
The lesswatts.org site is actually very good. They mention a few really interesting things besides the tickless kernel and the IRQ balancing, such as SATA Aggressive Link Power Management, which is slated to be included in kernel 2.6.24 or 2.6.25. It might be able to save us .5 to 1.5 watts per SATA drive. SWEET!
One problem I have with the site contents is that they also discuss powering down hard drives, without explaining that doing so can have a serious impact on the life span of a hard drive. Most hard drives can only stop and start a limited amount of times before failure, though laptop drives are supposed to be able to start and stop a lot more. What's more is that they also take up less energy in general, though they do cost more up front.
I emailed the admin of the site to ask about p4-clockmod, and they responded confirming that the module doesn't actually do any frequency scaling, and that it can sometimes reduce heat, but on newer processors it can actually increase power consumption. Ugh!
The biggest surprise I found there was that gigE can use up to more than 2 watts than 100Mbit. I was very surprised when I tested it and it was true.