It has 8. So It shows 8 in task manger. So does that mean that it should be also showing 8 in the bios?
task manager shows the number of available threads which for the hyperthreaded i7 it is 8. the Bios shows the number of cores which is 4 for the i7. An i7 is a quad core with hyperthreading which gives each core 2 threads which is why you see 8 boxes in task manager.
you are fine. your computer is as it should be.