DOS ain't dead

ACPI tools 1.3 (Announce)

posted by RayeR , CZ, 16.06.2026, 19:14

> Nowever, as you probably know, the ultimate slowdown program for DOS is
> CPUSPD
> https://www.vogons.org/viewtopic.php?t=74359
> https://www.vogons.org/viewtopic.php?t=74359

Yes, I just wanted to notice about CPUSPD, s oyou already know...
It has an unique feature of a minimum DOS SMP - multiprocessor support. As I read it's needed to do this trick to properly set lower multiplier on some kind of CPUs that requires to program MSR of ALL available cores. I though that under DOS all other cores (except boot one) are disabled/deep sleep and no maters how they are set. But not always true. If multiplier is set from lower value (set in SETUP) to higher value it seems to be enough to set MSR just on the boot core but when going from high value to lower value it's necessary program all cores - so this requred a minimum of MPS/APIC programming - cool!

And not just this. CPUSPD supports also ODCM and throttling methods, P-state changes, VID, L1/L2 cache enable/disable, branch prediction and prefetch enable/disable so it allows really wide CPU speed and power consumption variability. I tested on my SandyB and can lower multi from 45x down to 16x, P-state/ODCM/throttle not supported here. In most cases I don't need my DOS sprinting at 4,5GHz so it's fine to be able to relax it and spin down the fans... :)

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DOS gives me freedom to unlimited HW access.

Complete thread:

• ACPI tools 1.3 - Laaca, 16.06.2026, 00:28 (Announce)
  • ACPI tools 1.3 - mceric, 16.06.2026, 01:14
    • ACPI tools 1.3 - Laaca, 16.06.2026, 16:27
      • ACPI tools 1.3 - RayeR, 16.06.2026, 19:14
        • ACPI tools 1.3 - Laaca, 16.06.2026, 22:05
        • ACPI tools 1.3 - Zyzzle, 16.06.2026, 22:59
  • ACPI tools 1.3b - Laaca, 16.06.2026, 23:04
    • ACPI tools 1.3b - RayeR, 18.06.2026, 06:53
      • ACPI tools 1.3c - Laaca, 20.06.2026, 22:55