Hi are you asking if your Pentium 4 is a dual core?
Most Pentium 4 have hyperthreading which is 2 threads 1 core. Windows will see this as 2 Logical processing cores, you only have 1 physical core cpu. Also windows tend to make the second core real or not 1 Mhz less than the original core.
Early Pentium 4 was only single core without hyperthreading.
What is the problem you see?