Thank you Andrew for finding this! Many forums will tell you to re-install windows or to mess with the HAL in order to show multiple cores after changing processors. Kasey (one of our students) changed his quad-core processor to a hexacore processor. Once he booted up he only saw four cores. Andrew discovered an easy fix by using EasyBCD. Here’s what you do. Download EasyBCD
- Install the Software
- Run EasyBCD
- On the menu, Click on Advanced Settings
- Click Developer
- Limit Windows to (Change the CPUs to 0 Zero) – Yes this is correct
- Click Save
- Reboot
Once you reboot the task manager will show all of your cores.
EasyBCD is a boodloader that does so much more than fix the number of CPUs seen by your taskmanager. It allows you backup and restore your BCD settings, allows you to setup your MBR (Master Boot Record), repair boot files, helps you to diagnose boot problems, limit CPU or memory usage for older programs.