Can you post a screenshot of your taskmanager?I think that is where you are wrong, but i don't know how it exactly looks with a bulldozer CPU.
An Intel 4-core without hyperthreading shows 4 physical cores and 4 virtual cores. That does NOT mean there are 8 cores, because logical and virtual add up. The system only uses virtual cores! Even the system can not differentiate between what a virtual and a physical core is. And it doesn't need to, because that makes no sense at all.
An Intel 4-core with hyperthreading shows 4 physical and 8 virtual cores. It's still just 8 virtual cores, not 12 or whatever.
Also my 8-core Ryzen hast 8 physical and 16 virtual and it never becomes 24 cores in whatever way.
Should look like that:
https://community.amd.com/servlet/JiveServlet/showImage/2-2755232-112277/processor.png
So same as any other cpu with SMT. So from at least the OS-view it doesn't have 8 "real" cores.