I have a WinXP Pro PC running an AMD 4200+ X2 S939 CPU. I recently noticed that when running Task Manager only one core graph is showing. I ran CPUID & PC Wizard 2008 and both programs say I have only ONE core. PC Wizard says 2 cores w/ only one core enabled!

I checked Device Manager and Processor shows only one instance. I updated the driver thru the Device Manager and rebooted and everything looked back to normal...Two cores.

However after a later reboot my PC is back to only one core running. I have rerun driver update but now it says driver is latest. Also ran BIOS update, downloaded & installed various updates from AMD & MS, Googled for several hrs...But I can't find a solution. Is it hardware or Windows? I am totally stumped.

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AMD 4200+ X2 | MSI K8N Neo4 FI | ATI X1950 XT | 3GB G.SKILL RAM | PC P&C ATX Silencer 470 PSU | Lite-On 18X & NEC 16X DVD | 160GB WD & 300GB Seagate | Saitek Eclipse KB | Logitech G5 Mouse | Antec P180

It's probably windows related. Try a clean install, and see if that fixes it.

Try running CHKDSK /F from acmd prompt and reboot.

Mike

FourEyes did the motherboard board have a single core processor installed before while using the current install of XP?

I have been using the dual core CPU for about a yr. I only just recently noticed that one core was disabled.

If my feable mind still functions I seem to recall a conflict on certain chipsets between the Win update and AMD patch for dual cores. You could install either one for 'joy' on dual cores but if you installed both there would be config problems.

Hope this helps ...

Make sure your bios supports dual core. If so, make sure XP is using the correct HAL. In device manager under computer, it should be listed as ACPI Multiprocessor PC.

run the little amd dual core application from their wrbsite.

AMD Dual-Core Optimizer

Release Notes For
Version 1.0.0

March 22, 2006

---General Description---

AMD Dual-Core Optimizer utility synchronizes Time Stamp Counter (TSC) MSRs on AMD Dual-Core Processors.

---Improvement and Fixes---

Version 1.0.0
* This is the initial release

---Usage Notes---

* Run setup.exe for a full uninstall/install.

---Known Issues---

* None

---System Requirements---

* Microprocessor: AMD Athlon™ 64 X2 Dual-Core Processors

This software installs and operates under the following operating systems
* Microsoft® Windows® 2000
* Microsoft® Windows® XP
* Microsoft Windows XP Professional x64 Edition
* Microsoft Windows Server 2003 32-bit
* Microsoft Windows Server 2003 64-bit

Operating systems NOT supported are:
* Microsoft® Windows® NT 4.0
* Microsoft Windows 98 Gold
* Microsoft Windows 98
* Microsoft Windows 95 OSR2
* Microsoft Windows 3.x
* Microsoft Windows Millennium
* Microsoft Windows 98 Second Edition

---The following languages are supported ---
* All

I uninstalled the AMD dual-core driver and it seems to be OK for now. I read there may be a conflict e/ the NForce 4 chipset.

bump