The only difference between multiple cores on a single CPU vs multiple separate CPUs is licensing. MS at one point (when they still had the Home/Pro distinction but dualcore CPUs were becoming the norm in mid/low-end) decided to treat a dual core CPU as a single one for the point of licensing so that you could utilize a dualcore with Windows Home edition.
Technically the only distinction in Windows is between uniprocessor and multiprocessor HAL.
The latter is required to utilize multiple CPUs, multiple cores or indeed multiple threads in the same CPU.
Note that the practical performance gain of HT in P4 was negligible to indeed negative (higher overhead of multiprocessor HAL), particulary in games.
Here are some benchmarks:
https://www.tomshardware.com/reviews/single-c … ion,549-12.html
(Q3A, slightly slower with HT)
https://www.tomshardware.com/reviews/single-c … ion,549-14.html
(Comanche, one bench very slightly faster, one very slightly slower)
Where HT (and indeed SMP) shines is in predictable number crunching, such as with MP3 encoding:
https://www.tomshardware.com/reviews/single-c … ion,549-15.html
Or video encoding:
https://www.tomshardware.com/reviews/single-c … ion,549-16.html