At 19:22 -0700 6/10/11, [email protected] wrote: A batch of good stuff about power usage and clock speeds which I snipped.
Microprocessors built with complimentary symmetry metal oxide transistors, CMOS, dissipate power only as the states of the CMOS gates are changed. While sitting in a 1 or 0 state they don't require any power at all. So the usage of a chip is proportional to the count of gate changes per second and not only to the clock speed. In an idle state there might not be very many gates changing state at each clock pulse. (For completeness, the power is also proportional to the square of the power voltage.) Scientific calculations, games, video which has to be decompressed in real time, things like that require a lot of calculation and thus a lot of gate changes at any clock speed. Editing a document while being limited by your finger speed on a keyboard will not use many gate changes and the computer power will be lower. For a thermally limited cube you could measure the temperature and adjust the clock speed accordingly. If you try to play some war game that demands three dimensional viewing depending on your place in the synthetic environment your machine will slow down. Sorry. You can read your email at full speed. There is a lot of data on the world wide web about overclocking of chips. The idea originally was to monitor a chip for errors and speed up the clock until they begin to show up. The acronym was the TEA technique and I have forgotten the words it stands for. What you're talking about is underclocking but it's the same idea. Modern chips actually have temperature sensors on them; they can be read out and perhaps used as in input to a variable frequency clock. A maximum speed clock connected to a programmable downcounter chip would be pretty easy to set up, trivial if you could use a simple interface to code running on the processor itself but more difficult if Apple limits you to the likes of USB or Ethernet. There are also analog schemes for making a variable frequency oscillator that could be controlled by a thermistor on the heat sink. They would be slower to respond. -- --> If it's not on fire it's a software problem. <-- -- You received this message because you are a member of G-Group, a group for those using G3, G4, and G5 desktop Macs - with a particular focus on Power Macs. The list FAQ is at http://lowendmac.com/lists/g-list.shtml and our netiquette guide is at http://www.lowendmac.com/lists/netiquette.shtml To post to this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/g3-5-list
