Dynamic tick and HPET: the bcdedit timer settings, and why the usual advice is wrong
SHORT ANSWER
Dynamic tick lets Windows skip timer interrupts while idle to save power; disabling it with bcdedit keeps the tick constant. Critically, the correct action for HPET is usually to delete the useplatformclock setting rather than force it on — forcing HPET is a widely repeated recommendation that commonly reduces performance on modern hardware.
Exactly what it changes
Read straight from the application source. If a tool will not show you this, it is asking for trust it has not earned.
bcdedit /deletevalue disabledynamictickReturns dynamic tick to the Windows default. Deleting is the correct revert, not setting it to yes.
bcdedit /deletevalue useplatformclockStops forcing HPET as the platform timer, letting Windows choose. This is usually what you want.
What it does
Dynamic tick lets the kernel skip periodic timer interrupts when nothing needs servicing. Disabling it keeps a steady tick, which some people find produces more consistent timing behaviour.
The platform clock setting is separate and more consequential. Forcing HPET makes Windows use the High Precision Event Timer, which on most modern systems is slower to read than the invariant TSC the OS would otherwise pick.
When it helps
- Deleting a previously forced useplatformclock setting is a genuine fix, and often reverses a real performance loss someone inflicted on themselves following old advice.
- Disabling dynamic tick can marginally improve timing consistency on some systems.
When it hurts
- Disabling dynamic tick increases idle power draw — meaningful on laptops.
- Forcing HPET on is a common mistake that usually costs performance. If a guide tells you to set useplatformclock to true, be sceptical.
- The measurable effect of dynamic tick alone is small on current hardware.
How to undo it
Run the same commands — deleting these boot values returns Windows to choosing for itself, which is the safe state.
Verdict
The valuable half here is undoing forced HPET, not disabling dynamic tick. If you have ever followed an old timer-tweaking guide, check whether useplatformclock is set and remove it.
Related guides
Everything else we change is listed too
All 127 optimizations are published in full, with what each one does and which are free. You can apply any of them by hand using pages like this one — the tool exists to do it in one click and put it back after every Windows update.