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Unknown device: High Precision Event Timer?


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Apparently Windows 2000 and 2003 do not support High Precision Event Timer. Device Manager shows Code 28, but I've never seen "Unknown device" for this on new mobos. This one is a new AMD 880G + SB850.

PNPDeviceID : ACPI\PNP0103\4&356479D3&0

Any ideas?

Edited by Phenomic
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A google search of the Hardware ID shows that it corresponds to Atheros AR5xxx/AR9xxx Wireless driver;

However, this http://en.wikipedia....ion_Event_Timer says

Windows XP, SP2 knows the HPET timer (as a device with PNP0103 identifier). When detected (for example, on Intel DQ45CB motherboard), Device Manager (START / SETTINGS / CONTROL_PANEL / SYSTEM / DEVICE_MANAGER) shows "High Precision Event Timer" device in "System devices" branch. But this device has no driver and is not used at all.


Older operating systems do not support HPET and can only use older timing facilities, such as the programmable interval timer or the real-time clock..
Edited by Sp0iLedBrAt
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Thank you, this mobo does indeed have an Atheros AR9285 Wireless Network Adapter in a mini PCI-E slot, but it already has a driver and works just fine. This ACPI\PNP0103 seems like a dummy device because if I offer it the dummy "AMD Away" driver it accepts it and the unknown device goes away.

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Well I'm stumped with this mystery device. It's a Zotax miniITX mobo with AMD 880G+SB850, Win2000 installs just fine but the system is showing huge DPC latency spikes. I can't track it down to any device driver but it doesn't happen in Linux, so that proves that it's a software problem and not hardware/BIOS(?).

Funny thing, I didn't notice the latency or any multimedia stuttering BUT it makes my wii remote mouse jump like crazy every few seconds.

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OK fixed

High Precision Event Timer -- HPET

Device Not Available ACPI\PNP0103\4&356479D3&0

at 0xFED00000-0xFED003FF, for some reason this memory address is not available on this mobo.

To fix, I renamed "14140000FFFFFFFF" in:



I don't know how HPET got enabled. I used the unofficial Win2k SP5 for this build (does SP5 enable HPET by default?). The "unknown device" in Device MAnager is still there but is harmless. But the DPC latency spikes are gone... fixed! I was getting huge spikes every 10-20 seconds which made my Wiimote jump to the corners of the screen... phew.

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  • 4 years later...

Here is a fix for the HPET driver on Win2k. It was made by HP to fix the issue in server 2003, but works great under Windows 2000 too.

Edited by AnX
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