What is the standard value of Start?

Frozen Tweaks writes 3 when you switch the tweak off, which is the value it treats as the Windows standard. With the tweak on, Start is 4.

Is "Disable HPET Device" safe to switch on?

The useful part is making sure useplatformclock is not set. Disabling the device on top is mostly belt and braces. The main cost: On a default Windows install HPET is not the active clock, so disabling the device usually changes nothing.

Does it need a restart?

Yes, the change applies after a restart.

Is "Disable HPET Device" free in Frozen Tweaks?

It is part of Frozen Pro and Elite. You can also make the change by hand with the values on this page.

Should you disable HPET for gaming? What the HPET device and useplatformclock do

Frost LIVECPUProUndo: YesUpdated Oct 8, 2026View as Markdown

Short answer

Updated Oct 8, 2026

HPET is a hardware timer on the motherboard. Windows normally keeps time with the processor's own counter (TSC) and uses HPET only when told to. This tweak disables the HPET device driver in Windows, so the system cannot fall back to it. In the registry it sets Start to 4 under HKLM\SYSTEM\CurrentControlSet\Services\hpet.

In the app

Disable HPET DevicePRO

Registry

HKLMSYSTEM\CurrentControlSet\Services\hpet

Start34

What the switch writes. Your current value may differ.

What it does

In the app the switch is called "Disable HPET Device", described there as: Disables HPET driver to favor TSC/HPET-free timing path (reboot).

When it helps, and when it hurts

When it helps

Systems where HPET was forced on (bcdedit useplatformclock true), which makes timer calls slower and can lower frame rates.

When it hurts

On a default Windows install HPET is not the active clock, so disabling the device usually changes nothing.
A few systems and tools expect the device to exist. If timing or audio behaves oddly afterwards, switch it back.

What it writes

Exactly what the switch changes, read from the app's source. Switching it off is what the app writes when you turn the tweak off again.

Registry values the switch writes.
Key and value	With the tweak	Switching it off
HKLMSYSTEM\CurrentControlSet\Services\hpetStart	4	3

From the app's source (hpet_device_off.hpp), app 2.0.0, checked Oct 8, 2026.

The same change by hand

You do not need the app for this one. These commands make the changes from the table above. Run them in a Command Prompt opened as administrator, and make a restore point first.

Make the change · CMD

reg add "HKLM\SYSTEM\CurrentControlSet\Services\hpet" /v "Start" /t REG_DWORD /d 4 /f

Put it back · CMD

reg add "HKLM\SYSTEM\CurrentControlSet\Services\hpet" /v "Start" /t REG_DWORD /d 3 /f

See what it is set to now · CMD

reg query "HKLM\SYSTEM\CurrentControlSet\Services\hpet" /v "Start"

How to undo it

In the app: Yes

Switching it off sets a standard Windows value, which may not be exactly how you had it.

Switch the tweak off in Frozen Tweaks. It writes Start back to 3.

Changing several settings at once? The app's Make a restore point button, on every plan, makes a Windows restore point before you start.

Verdict

The useful part is making sure useplatformclock is not set. Disabling the device on top is mostly belt and braces.

Questions

What does the "Disable HPET Device" tweak change in Windows?: In the registry it sets Start to 4 under HKLM\SYSTEM\CurrentControlSet\Services\hpet.
What is the standard value of Start?: Frozen Tweaks writes 3 when you switch the tweak off, which is the value it treats as the Windows standard. With the tweak on, Start is 4.
Is "Disable HPET Device" safe to switch on?: The useful part is making sure useplatformclock is not set. Disabling the device on top is mostly belt and braces. The main cost: On a default Windows install HPET is not the active clock, so disabling the device usually changes nothing.
How do I undo it?: Switch the tweak off in Frozen Tweaks. Switching it off sets a standard Windows value, which may not be exactly how you had it.
Does it need a restart?: Yes, the change applies after a restart.
Is "Disable HPET Device" free in Frozen Tweaks?: It is part of Frozen Pro and Elite. You can also make the change by hand with the values on this page.

In the app