intelman said:QuickC said:*snip*
Pretty sure Windows 7 can distinguish HT cores from real cores. Perhaps that is why 4 are unused.
WIn 7 is surely tuned for Hyper threading, there is no real and hyper cores however. Each cpu has two threads of code being feed it. The cpu then looks for stalls, memory read, FPU process, or and answer from another cpu, when it finds a stall it switches to the other thread of code to keep the cpu 100% filled with instructions.
Keep in mind on a 3ghz machine, reading a memory location that isnt in the cpu cache could take 20-100 cycles of the cpu, if the memory has been written to virtual memory it could take 1000-10000 cycles before it can get back to work.
Also, before win7, each spoftware thread was tightly coupled to a particula core, that coupling can be loose between to hyper cores.