Below are hyperlinks to the topics of dual core/ processor support in windows vista home / premium, just click on the relevant link
It is little known that not all versions of Windows Vista provide support for dual processors. here are some work arounds and information on how to enable support.
Disclaimer note: any information provided here is for reference only, any system changes you make you do so at your own risk.
How to enable multi processor support in vista home, premium.
View dual core processors in task manager / show both cores.
"While all editions of Windows Vista can support multiple core CPUs, only
Windows Vista Business, Ultimate, and Enterprise can support dual
processors"
I bought Windows Home Premium. I have a dual processor workstation. Each
processor is quad-core XEON 5355. Only one got installed, so my task manager
only shows 4 cores, and DxDiag only shows one processor.
In XP Pro I see all 8 cores. Did I get the wrong version of Vista?