Hi
You may refer to below link to change the CPU Cores.
http://smallbusiness.chron.com/set-number-cores-windows-29171.html
And as per your unit specification, it has 4 cores/8 threads, as you have already enabled Hyperthreading in BIOS, it should give you the required output.
Refer to below link and Find out how many cores your processor has :
http://windows.microsoft.com/en-us/windows-10/find-out-how-many-cores-your-processor-has
I hope that answers your question. 
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