Renegat3
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« on: June 18, 2009, 22:14:30 » |
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Dynamic CPU frequency scaling (aka CPU throttling) is a function, that controls the speed of a CPU on the fly. If in idle mode, the CPU clock is decreased to a minimum level, and if needed it is increased to the maximum again. This was developed especially for mobile CPUs to preserve/prolong battery power. AMD's technology was named PowerNow! and Intel's Speedstep.
Since the AMD Athlon 64 and Intel Core generation, frequency scaling is a standard function for Desktop CPUs as well. However, the idea of dynamic scaling on desktop cpus is not aimed at perserving power but to run the CPU cooler. Thus AMD called their technology for the desktop/server CPUs Cool'N'Quiet. Quiet, because the CPU fan can run slower and thus quieter.
However, there is an exception. The low power socket A CPU AMD Geode NX, based on the Athlon XP T-bred core, also supports frequency scaling, eventhough it's not a mobile CPU. Nonetheless, it's a K7 CPU but works slightly different. As such, it does not work with the powernow-k7 module.
powernow-nx is a patched version of the powernow-k7 module, which in turn soley works with the Geode NX. The scaling function in DL (since 1.8.0) recognizes the Geode NX and loads the powernow-nx module accordingly.
However, identifying the CPU as Geode NX seems only possible, if the BIOS identifies it as such first. Some BIOS might only see an Athlon XP. In that case, the scaling is not turned on automatically and has to be done manually.
There are 3 models: 1250+, 1500+ and 1750+. Since the 1250+ only runs on 666MHz, scaling doesn't really make sense. Therefore only the 1500+ and 1750+ are supported. The latter is the most commom on "standard" desktop PCs, while the others are found in thin clients.
The scaling function in DL (since 1.8.0) was tested on a Geode NX 1750+. I can't tell if it works just as well for the 1500+. To improve performance, I advice the run the FSB at 133MHz. If you want to run it slower, set it to 100MHz (in the BIOS, or via jumper on your mainboard).
R3
The Geode NX 2001 does NOT belong to the NX series! It is merely a relabled XP 2200+ T-bred with an unlocked multiplier. Thus it will most likely not work with the powernow-nx module. I'm not even sure it supports Powernow!.
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