Upgrade from Core2Duo to Quad core only shows 2 cores in task manager (0/1)

[I Drive Fast]

I recently upgraded my Vista64 Ultimate from an E8600 to a Q9550.

In the task manager, it only shows 2 cores.

Device Manager shows all 4 CPU's.
Bios shows all 4 CPU's.

Any ideas on how to correct this?

Attached are screen shots showing the problem.

 

[pacca]

on task manager click on view ,1 graph per cpu,that should do it.

 

[Richard G. Harper]

Reinstall Windows.

 

[Colin Barnhorst]

Reinstall Windows.

Why? The ACPI driver for Vista x64 is the same for all systems so why
reinstall?

 

[Ian D]

I recently upgraded my Vista64 Ultimate from an E8600 to a Q9550.

In the task manager, it only shows 2 cores.

Device Manager shows all 4 CPU's.
Bios shows all 4 CPU's.

Any ideas on how to correct this?

Attached are screen shots showing the problem.

Since Device Manager shows all 4 cores, there's probably no
problem with Vista itself. For a second opinion, get CPU-Z
from cpuid.com. If it reports 4 CPUs, the issue is with Task
Manager only. The fact that TM sees 2 cores indicates that the
system is correctly identified as an ACPI Multiprocessor system.
A check with Device Manager will confirm this.

Besides CPU info, CPU-Z gives detailed memory info.