New cpu not working correctly

[bloodshatermaster]

I have recently purchased a new cpu mobo combo from SCAN UK it was a MSI Z370 carbon pro gaming mobo with a intel i5 8600k 6 core 6 thread cpu but windows ten is only showing 4 cores and 4 threads in use and cpu-z also shows the same but my mobo recognises that it is a 6 core cpu but only allows 5 cores to be selected when in options i have noticed the cpu underperfoming and want to know why this is happening can someone please help me?

 

[vMax]

1- How did you instal Windows 10? was it a clean install?
2- Go into task manager and click on "Performance". This will make a graph of the use of each thread. Does it show 6 cores?
3 - Go into BIOS and load optimised defaults - make sure multi-core enhancement is on.
Also make sure your power profile is set to balanced and also try performance..

If needed try this...
4- Check the setting in msconfig -> startup -> windows 10 -> advanced settings -> amount of cpus.
It should be unticked.

I am not an expert, so hopefully others can chime in and help...