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To reduce problems with emitted Radio Frequency Interference, most processors now use a clock that varies in speed over time. This doesn't really reduce the emitted energy, but because it is always changing frequency interference with other devices tends to be intermittent, and Ideally unnoticeable. Also the oscillators used in computers are not the most precise, they don't need to be and precision cost. The bios may let you toggle this deliberate frequency variation and off, which I suppose could be critical in some real-time cases, or a varying clock may, in some cases cause objectionable interference where as the fixed clock, may not, YMMV. |
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Sent with ProtonMail Secure Email. |
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‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐ |
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On Wednesday, March 4, 2020 5:28 PM, Walter Dnes <waltdnes@××××××××.org> wrote: |
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> I've cobbled together a script to select cpu governors and speeds. |
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> One weird thing I've noticed is that reported cpu speed doesn't quite |
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> match the selected speed. E.g. on my machine (yours will vary)... |
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> |
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> cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_available_frequencies |
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> |
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> ...shows avalable speeds... |
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> |
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> 3001000 3000000 2900000 2800000 2700000 2600000 2500000 2400000 2300000 2200000 2100000 2000000 1900000 1800000 1700000 1600000 |
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> |
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> IMPORTANT "userspace" governor must be present. |
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> |
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> /sys/devices/system/cpu/cpu0/cpufreq/scaling_cur_freq reports speeds |
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> very close to, but slightly lower than the selected values, and they also |
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> seem to jump around a bit. What gives? |
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> |
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> ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
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> |
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> Walter Dnes waltdnes@××××××××.org |
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> I don't run "desktop environments"; I run useful applications |
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